A shaver that used to feel smooth and now tugs has almost always got a worn head, not a failing motor. Foils are consumable parts. Knowing when they are done saves you both discomfort and the cost of replacing a device that was fine.
What actually wears out
Two parts wear at different rates.
The foil is the thin perforated screen you can see. It is thin by design — that is what lets the blade cut close without touching skin. Over months it thins further through friction, and eventually develops microscopic tears or a shiny worn patch.
The cutter is the blade underneath, which you do not see. It dulls more slowly than the foil thins, but it does dull.
Replace them together where the head is sold as a unit. A new foil over a dull cutter still tugs.
The signals
Do not track this by calendar alone. Your own use decides it. Watch for:
Tugging or pulling. The clearest signal. A sharp head cuts hair without you feeling it caught.
Needing more passes. If an area that used to take one pass now takes three, the head is not cutting efficiently. This one matters most, because extra passes are what irritate skin.
Heat. A worn head generates more friction against the skin for the same result.
Visible damage. Hold the foil to the light. Any tear, dent, or bright polished patch means replace it now — a torn foil can nick you, which is the one thing a foil shaver is supposed to prevent.
A rough interval
For body shaving two or three times a week, most foil sets last somewhere between six and twelve months. Shaving daily, or over large areas like both legs each time, puts you at the shorter end. It is a range, not a rule — the signals above override it.
How to make them last
Rinse after every session. Hair and dead skin behind the foil are abrasive. Leaving them there grinds the parts against each other. This is the single biggest factor.
Do not towel-dry the foil. Tap off the water and let it air dry. A towel snags and deforms a screen that is only microns thick.
Stop pressing. Pressure wears the foil faster and does not shave closer.
Cap it. A head knocked against other things in a drawer dents, and a dent is a worn patch waiting to happen.
The false economy
Running a worn head to save the cost of a replacement means shaving with a tool that requires more passes over the same skin. The irritation you get is not your skin being difficult — it is a maintenance issue with a straightforward fix.
The Veloura razor has a head unit that comes off for rinsing, which is what makes the routine above practical.
More on the maintenance-irritation link in electric shaving for sensitive skin.