Watch winders and storage: what you actually need

A watch winder is a motorised box that rotates an automatic watch so its rotor keeps the mainspring wound while the watch is off your wrist. It does not maintain the watch, improve its accuracy or extend the life of anything.

There is one situation where a winder earns its place: a watch with a complication that is tedious or risky to reset. Beyond that it buys you convenience, and there is nothing wrong with buying convenience provided you know that is what you are buying.

The one genuine use case

A perpetual calendar tracks date, day, month and leap year, and on most designs knows the length of every month until 2100. Reset one from a dead stop and you may be working through a manual with several recessed correctors and a pusher tool, advancing the calendar day by day to bring it round. It is a job of many minutes, and doing it in the wrong sequence or at the wrong hour can damage the mechanism. A winder means you never have to.

An annual calendar is the same argument at lower intensity: it handles every month except February, so it needs one correction a year rather than one a month. A moonphase drifts slowly out of step and is fiddly to reset, since it must be advanced in whole days from a known new moon, and a world timer with a 24-city ring and a linked date can be equally awkward. Our guides to annual and perpetual calendars and GMT and world time watches set out what each mechanism has to be told when it stops.

If your watch shows hours, minutes, seconds and a date, resetting takes about fifteen seconds. That is the entire cost a winder saves you.

Does running a watch on a winder cause wear?

This argument goes round in circles online, and both sides have a real point.

The wear argument. A movement running is a movement wearing. Pivots turn in jewels, the escapement locks and impulses tens of thousands of times an hour, and the oil separating those surfaces is worked and spread. A watch kept running continuously accumulates more running hours than one worn three days a week, and running hours wear parts.

The stationary argument. Lubricants degrade with time as well as with use. They oxidise, thin, migrate and eventually dry. A watch that sits still for five years has aged its oils almost as much as one that ran for five years, without the benefit of the oil being kept distributed.

Neither effect dominates for a watch serviced on a sensible schedule. Modern jeweled movements are designed to run continuously; that is what they do on your wrist and on a watchmaker's bench for days after a service. If you service on the symptoms and outer limits described in our servicing guide, a winder will not measurably shorten the watch's life, and leaving it stopped will not measurably extend it.

What a winder does not do is delay a service. The clock on lubricant aging runs regardless.

Specifying a winder properly

This is where most winder purchases go wrong. Two settings matter, and a winder that cannot be set to both is a decoration.

Turns per day

Turns per day (TPD) is the number of full rotations the winder gives the watch in 24 hours. The requirement varies by movement, since it depends on how efficiently the rotor delivers energy and how much the mainspring needs.

If TPD is too low, the watch never reaches full wind. It will keep running, but it spends its life in the lower part of its power reserve, where torque is lower and the rate less stable. If TPD is far higher than needed, the watch sits at full wind with the mainspring bridle slipping in the barrel, which is harmless in itself but means the movement runs more hours than it needs to.

Winders typically offer a few hundred to around two thousand TPD. Published requirements for common automatics generally sit in the lower half of that band, and the honest advice is to find the figure rather than guess: check the owner manual, the movement maker's documentation for your caliber (ETA, Sellita, Miyota and Seiko all publish specification sheets), or ask the watchmaker who services it.

Direction

Automatic winding systems fall into three groups, and the winder must match.

• Bidirectional. The rotor winds the mainspring turning either way, through reversing wheels or a pawl system. Many workhorse calibers including the ETA 2824-2 family work this way.
• Unidirectional. The rotor only winds in one direction and freewheels in the other. The widely used Miyota 8215 is a well-known example.
• Unknown, which describes most owners.

If you do not know, set the winder to bidirectional or to an alternating program. A bidirectional setting winds a unidirectional movement perfectly well and simply wastes half its rotations, whereas a unidirectional setting turning the wrong way winds nothing at all. Our guide to automatic versus manual winding explains the mechanisms involved.

Magnetism, noise and build

A winder puts an electric motor within a few centimeters of a balance spring for years at a time, and motors contain magnets. This is a real consideration rather than a theoretical one, and one of the few genuine arguments for spending more: better winders position the motor away from the watch, shield it, or both.

Most modern watches are more robust than they used to be, and a movement built to ISO 764 for magnetic resistant watches must survive a direct current field of 4,800 A/m and keep running within a defined rate deviation afterwards. Silicon hairsprings and soft-iron inner cases protect better still. But a cheap winder with an unshielded motor pressed against the caseback is an avoidable risk, and if a watch that lives on a winder starts gaining minutes a day, magnetism is the first thing to test: see magnetism and watches.

Noise matters more than buyers expect, since winders usually live in bedrooms. A good one is inaudible from a meter away and runs in short bursts with long rests. A bad one hums continuously.

So what do you need?

A watch roll (a soft padded tube with individual pockets) or a plain lined box does everything most owners need, costs a fraction of a winder, contains no motor and needs no power. It is the sensible default, and what most collectors actually use for most of their watches.

Storing watches properly

From a night to a few weeks, storage is trivial: crown pushed in or screwed down, somewhere clean, dry and away from magnets and radiators. For longer, a few things genuinely matter.

• Let the watch wind down. There is no benefit to storing a mainspring under full tension for years, and a wound-down watch is a stopped watch, which is what you want.
• Screw the crown in. An unsealed crown lets humidity into the case, and humidity is what rusts steel parts.
• Keep it cool, dry and stable. Not a loft, garage, bathroom or windowsill.
• Add a silica gel sachet to the box and dry or replace it periodically. Cheap insurance in a damp climate.
• Avoid a sealed leather box in a humid room. Leather absorbs and holds moisture, and it will hold it against your watch.
• Take leather straps off watches stored for years. They dry, crack and can stain a case.
• Check on them twice a year. That is how you notice a dial spot or a corroding crown while it is still a repair rather than a loss.

Travel and transit

For hand luggage, a padded single-watch pouch or a two-slot zip case is enough. Watches are best kept with you: they are small, valuable and easy to lose.

If a watch must go in checked baggage, treat it as a shock and theft problem. Wind it down, use a hard case rather than a soft roll, wrap it in clothing at the center of the bag rather than the edges, and accept that most travel insurance and airline liability terms exclude or heavily limit watches in checked bags. Check your own policy wording rather than assuming.

Two footnotes. Photograph every watch, front, back and clasp, and record serial and reference numbers somewhere that is not in the same house as the watch: insurers, police and the pre-owned market all work from those numbers. And check the single-item limit on your home contents policy before assuming a watch is covered, at home or away, a point our guide to building a collection goes into.