Collectors
- Mechanical movements run on a wound spring. Automatic is a mechanical that winds itself from wrist motion; manual needs winding by hand.
- Quartz movements run on a battery and a vibrating crystal. They are far more accurate and far cheaper to own.
- The accuracy gap is not close: a mechanical watch is specified in seconds per day; ordinary quartz in seconds per month. That is a difference of ten to thirty times.
- Light-powered quartz gets you quartz accuracy with no battery changes. It is the low-maintenance option nobody talks about enough.
Mechanical: Automatic and Manual
A mechanical movement stores energy in a coiled mainspring and releases it in tiny measured increments. The regulating organ - a balance wheel oscillating against a hairspring - is what makes those increments even, and the escapement is what lets the gear train advance one step at a time. Every tick you hear is that system doing its job, and nothing in it needs electricity.
A manual movement is wound by turning the crown, typically every day or two. An automatic movement adds a weighted rotor that spins as your wrist moves and winds the mainspring for you. Automatics are the overwhelming majority of mechanical watches sold, and the trade-off is thickness: the rotor sits on top of the movement and adds height.
Two numbers describe a mechanical movement's character. Power reserve is how long it runs fully wound and unworn - roughly forty hours is traditional, and the modern selling point is around eighty, which gets a watch through a weekend in a drawer. Beat rate, given in vibrations per hour, is how finely it slices a second: 28,800 vph is eight beats per second and the common modern standard, which is why the seconds hand appears to sweep rather than tick.
Accuracy is where expectations need managing, and the numbers get quoted loosely. Unregulated movements from the big Swiss suppliers are specified in grades running from roughly plus or minus twelve seconds a day down to about plus or minus four for the top grade, which is where the commonly cited five-to-fifteen-seconds-a-day figure comes from. A watch that has actually been regulated by a watchmaker should sit within a few seconds a day.
The strictest common benchmark is COSC certification, which tests uncased movements over fifteen days in five positions and three temperatures. Its headline criterion is a mean daily rate between four seconds slow and six seconds fast, but that is one of seven eliminatory tests rather than the whole standard, certification is optional and covers only a minority of Swiss movements, and a certified movement can run outside that window once it is in a case on a wrist. Other bodies - Besançon in France, and manufacturer programmes that test the finished watch - work to their own criteria.
All of which is a remarkable achievement of mechanical engineering, and all of it is still comfortably worse than a supermarket quartz watch. Buying mechanical is a choice about what you want to own, not about telling the time better.
Quartz: How It Actually Works
A quartz movement passes current from a battery through a tiny quartz crystal, cut so that it vibrates at a very stable frequency - 32,768 times per second, chosen because repeatedly halving that number fifteen times gives exactly one pulse per second. A circuit counts those pulses and drives a stepper motor that advances the seconds hand, conventionally once per second, which is the ticking you see. High-frequency quartz movements step many times a second instead and produce a sweeping hand - the Bulova Precisionist in our chronograph roundup is one of them, which is why a quartz watch can sometimes look mechanical.
The accuracy that produces is in a different league: mass-market quartz is typically specified at somewhere between fifteen and thirty seconds a month, and high-accuracy quartz movements do considerably better. Temperature is the main thing that degrades it, which is why the best quartz movements are thermocompensated.
Ownership is simpler too. A battery lasts a few years and costs very little to replace, though it should be done by someone who will reseal the case properly on a water-resistant watch. There is no service interval in the mechanical sense. The honest summary is that quartz is better at being a watch and mechanical is better at being an object, and most collectors own both while claiming to prefer one.
Light-Powered and the Other Hybrids
Light-powered quartz - Citizen calls it Eco-Drive, other brands use their own names - puts a photovoltaic cell under the dial and stores the energy in a rechargeable cell instead of a disposable battery. Ordinary daylight and even indoor light keep it running, Citizen states that a full charge lasts more than six months in the dark, and there is no routine battery change to book. The rechargeable cell is still a consumable, replaced at service after well over a decade rather than every few years. For a watch that gets worn occasionally rather than daily, this is the most practical movement type available, and it is why both Citizen picks in our chronograph roundup use it. Our Eco-Drive guide goes deeper.
Kinetic, which is Seiko's name for it, and auto-quartz movements generally use a mechanical rotor to generate electricity for a quartz regulator - self-winding accuracy without the light dependency. Spring Drive replaces the escapement in a mechanical movement with an electromagnetic brake regulated by a quartz crystal, producing a genuinely gliding seconds hand and accuracy far beyond ordinary mechanical. Mecaquartz pairs a quartz timekeeping base with a mechanical chronograph module, which is why some affordable chronographs have a satisfyingly snappy pusher.
None of these is a compromise in the pejorative sense. They exist because the two main families each have an obvious weakness, and each hybrid attacks one of them.
Jewels, Servicing, and the Numbers on the Caseback
The jewel count stamped on a movement - seventeen jewels, twenty-one jewels - refers to synthetic ruby bearings set where metal pivots would otherwise wear. They are there for friction and longevity, not decoration or value. More jewels does not mean a better watch beyond the point where the bearings that matter are jewelled, and inflated jewel counts were a marketing trick for decades.
Servicing is the real cost difference. A mechanical movement needs stripping, cleaning, re-oiling, and regulating periodically, because lubricants degrade and dry oil accelerates wear. The commonly cited interval is every five to ten years, and it is not cheap - on some watches a service costs a meaningful fraction of what the watch cost. Quartz needs a battery and a gasket check; light-powered needs only the gasket check and, eventually, a new rechargeable cell.
One number worth ignoring: an exhibition caseback tells you nothing about quality. Plenty of beautifully finished movements are hidden and plenty of plain ones are on display. Look at the finishing itself if you care - the quality of the bevelling and the texture of the plates - rather than at whether you can see it.
Which One Should You Buy?
If you want the watch to keep excellent time with no thought, buy light-powered quartz. It is the answer we think most people should hear and rarely do, because it is unglamorous and enthusiast writing skips past it.
If you want to own a small machine, buy mechanical, and buy automatic unless you specifically enjoy the ritual of winding. Accept the accuracy, accept the service bills, and accept that it will stop if you leave it alone for a few days - or use a winder, which our winder guide covers, including when one is genuinely unnecessary.
And if you want a mechanical watch's feel without its demands, the hybrids are worth a look. Our automatics under a thousand guide covers the entry point to mechanical properly. The one thing not to do is buy mechanical because you think it is more accurate. It is not - quartz is ahead by something like ten to thirty times - and the people who love mechanical watches most are the first to say so.
Frequently Asked Questions
What is the difference between automatic and quartz?
An automatic is a mechanical watch that winds itself from wrist motion, running on a spring and a balance wheel. A quartz watch runs on a battery and a vibrating crystal. Quartz is far more accurate and far cheaper to own; automatic is the more interesting object and needs periodic servicing.
How accurate is an automatic watch?
Unregulated movements are specified in grades from about plus or minus twelve seconds a day down to plus or minus four for the top grade, which is where the familiar five-to-fifteen-seconds figure comes from; one properly regulated by a watchmaker should hold within a few seconds a day. COSC certification, which tests uncased movements, requires a mean daily rate between four seconds slow and six fast among six other criteria - but it is optional, covers a minority of movements, and a certified movement can drift outside that range once cased. All of it is excellent for a mechanical device and considerably worse than any quartz watch.
Do automatic watches stop if you do not wear them?
Yes. Once the mainspring runs down the watch stops - typically after about forty hours off the wrist, or around eighty on movements with an extended power reserve. Wind it and reset it, or keep it on a winder if resetting a calendar every few days would irritate you.
What does the jewel count on a watch mean?
The number of synthetic ruby bearings set at friction points inside the movement, to reduce wear. Seventeen is the classic figure for a fully jewelled basic movement. Beyond the bearings that actually need jewelling, a higher count adds nothing, and inflated counts were long used as a marketing device.
Do quartz watches need servicing?
Very little. A battery every few years, ideally fitted by someone who will replace the case gasket and pressure-test a water-resistant watch. There is no equivalent to the mechanical strip-and-lubricate service. Light-powered quartz needs less still - no routine battery change, though the rechargeable cell is eventually replaced at service and gaskets still age.
What is Eco-Drive and is it better than a battery?
Eco-Drive is Citizen's light-powered quartz technology: a cell under the dial converts light into electricity stored in a rechargeable power cell. For most owners it is better than a disposable battery, because there is no routine appointment to make and no case opened every few years. Citizen states a full charge lasts more than six months in the dark. The rechargeable cell does eventually need replacing, but on a timescale measured in many years rather than a few.
Is a mechanical watch better than a quartz one?
Not at telling the time - quartz wins by ten to thirty times on accuracy, and on cost of ownership. Mechanical watches are bought for the craft, the movement, and the fact that nothing electronic is involved. Both positions are reasonable; only one of them is about performance.
Related Guides
How We Research
Our guides draw on manufacturer documentation, established industry practice, and what we learn testing and researching products for our buying guides. Where practice varies or opinion divides, we say so rather than pretending at consensus.
Setting note: On any mechanical watch with a date, keep the hands clear of the date-change window - roughly nine in the evening to three in the morning - before using a quickset date. The calendar works are engaged during that period and forcing them is a recognised way to damage a date wheel.