01 · Why it's neededThe oils dry out. The parts wear.
A mechanical watch isn't self-sufficient forever. Inside it flow specialized lubricants — oils for pivots, greases for gear teeth, specific products for the escapement — that let 150+ components move with minimal friction. Over time, heat, air exposure, and temperature cycles cause these oils to dry out, oxidize or migrate away from the surfaces they were applied to.
When lubricants fail, friction increases. The balance wheel oscillates with less energy — amplitude drops. The gear train works harder — wear accelerates. The escapement doesn't receive the right impulse — rate becomes unstable. If left too long, metal parts run dry against each other: an overhaul that would have cost €200 becomes one requiring replacement parts costing €500-800.
The industry rule of thumb is 5-7 years for a standard mechanical movement in good operating conditions. That's not an absolute deadline — it's a window. A watch worn rarely and stored well can wait 8-9 years; one worn daily in a dusty or humid environment needs attention sooner. WatchScope gives you the tools to know where you are in that window.
02 · The signalsWhen the watch is asking for help.
The signs of a watch approaching service are often subtle and gradual — they don't all arrive at once, usually one at a time. Learn to recognize them:
Falling amplitude
The balance wheel swings less and less: dropping from 280° to 230° over months, then below 200°. Friction builds, the movement becomes sluggish. WatchScope measures it in real time.
First signalReduced power reserve
A movement that used to last 48 hours now runs down in 30. Parts aren't flowing freely; the mainspring works against greater resistance than intended.
Clear signalErratic rate
Rate becomes unstable and variable: +15 s/d one day, +35 the next. Dry oils create uneven friction on the escapement.
Advanced signalUnusual sounds
Tic-tac that sounds different — heavier, irregular or 'scratchy'. Beat that stops and restarts. This stage indicates mechanical wear already in progress.
UrgentThe signals don't all show at once: usually amplitude drops first, then power reserve, then rate becomes unstable. Unusual sounds are last — and indicate mechanical damage is already underway. Don't wait to hear them.
03 · How oftenThe right interval depends on the watch.
There's no single answer that applies to all. The service interval depends on the movement type, intensity of use and environmental conditions. A guide:
- Standard mechanical movement (ETA, Sellita, Miyota, Valjoux): every 5-7 years. Covers the vast majority of quality modern mechanical watches.
- Mechanical chronograph: every 3-5 years. More moving parts than a simple automatic; the coupling mechanism and chronograph columns wear faster.
- Vintage watch (pre-1990): every 3-5 years. Period materials (oils, gaskets, alloys) degrade faster than their modern equivalents.
- ISO 6425-certified dive watch: every 2-3 years. Water-resistance gaskets must be tested and replaced regularly; the mechanical overhaul is done at the same time.
A watch worn every day accumulates about 28,000 balance wheel oscillations per hour — more than 240 million per year. One worn once a week accumulates roughly 34 million. It's no surprise that daily use consumes lubricants faster: plan the service towards the lower end of the interval if you wear the watch every day.
04 · WatchScopeAmplitude as the oil indicator.
Among all the parameters WatchScope measures, amplitude is the most sensitive to lubricant decline. Here's why: as oils dry out, friction on the balance wheel pivots increases. The balance wheel receives less energy from the gear train with each oscillation — and swings less. Amplitude drops.
This decline is slow and progressive — it doesn't happen overnight. A freshly serviced watch might start at 280°; after 3 years it might be at 255°; after 6 years at 215°. WatchScope lets you track this curve over time, rather than discovering the problem only when the watch stops. How to use it:
- Baseline after service: run a WatchScope test in the days after the overhaul and note the reference amplitude (typically 260-290°). This is your starting point.
- Test every 6-12 months: repeat the test under the same conditions (same wind level, same position). Log the results in WatchScope's watch history.
- Interpret the trend: a drop of 20-30° from baseline is normal after 2-3 years. A 50-60° drop means service is approaching. Below 200° amplitude is urgent.
Many watchmakers use only rate as an indicator. But rate can stay stable even with very dry oils — as long as the escapement functions, the balance keeps its rhythm. Amplitude, on the other hand, drops before rate becomes unstable. That's why WatchScope, measuring both, is a more complete early-diagnosis tool than simply watching the time.
05 · The overhaulWhat happens in the workshop.
Understanding what happens during a service reduces anxiety and helps you evaluate whether the watchmaker's quote is justified. A full service of a mechanical movement includes:
- Full disassembly: every single component is separated — balance wheel, hairspring, wheels, pinions, plate, bridges — and catalogued. A medium-complexity movement has 150-200 parts.
- Ultrasonic cleaning: components are immersed in specific solvents and ultrasonically agitated to remove old oils, oxides and residues. No mechanical tool touches the finished surfaces.
- Inspection and replacement: every part is examined under a microscope. Worn balance springs, chipped teeth, cracked jewels are replaced. The mainspring is often changed.
- Lubrication and reassembly: lubricants are applied with surgical precision — too much is as damaging as too little. The movement is reassembled and regulated on the bench.
- Final testing: the movement is tested for at least 24-48 hours in multiple positions, checking rate, amplitude and beat error. For watches with guaranteed water resistance, pneumatic pressure testing.
A full service of a medium-complexity mechanical movement starts at €150-250 at a qualified independent watchmaker, and can rise significantly for chronographs, vintage movements, or brands requiring original parts. Turnaround is 2-8 weeks. A service at the brand's official centre is typically 2-4 times more expensive but uses certified original parts.
Servicing a Mechanical Watch: Common Questions
How often should a mechanical watch be serviced?
With modern synthetic oils, a full service every 4 to 7 years is a sensible window for most movements, though it depends on how often you wear the watch and the caliber itself. The key is not to wait until it stops: by then the oils are already dry and metal runs against metal, accelerating wear. A watch that suddenly loses amplitude or starts drifting is asking for attention well before it ever halts.
How much does a watch service cost?
As a rough guide, a base ETA or Sellita movement typically runs around 100 to 150 € for a standard service. A manufacture or luxury caliber can climb to 400 to 800 € and well beyond, especially with chronographs or other complications. Prices vary a lot by country and by how much wear the watchmaker finds: a fresh movement just needs cleaning and oiling, while replacing worn parts adds to the bill.
What are the signs that a watch needs servicing?
The clearest signal is amplitude in steady decline: as the oils dry, the balance wheel swings with less energy. Watch also for rate that drifts away from its usual figure, a noticeably shorter power reserve, and a rate that scatters between positions where it once stayed tight. This is exactly where WatchScope earns its keep: by measuring amplitude, rate and beat error session after session, it lets you spot the downward trend long before the watch ever stops.
How long do mechanical watches last?
Generations, if they are looked after. A mechanical movement is fully rebuildable: every worn pivot, spring or jewel can be replaced, so there is no fixed expiry date on the watch itself. What keeps it alive is regular maintenance, not luck. Plenty of pieces from the 1950s and earlier still run within a few seconds a day today, precisely because they have been serviced on time rather than left to grind themselves dry.
Measure the amplitude now,
for free.
WatchScope tells you in 30 seconds where your watch stands in its lifecycle. Keep a record: it's the most valuable documentation you can have before taking it to a watchmaker.