Measure before guessing
If possible, note how many seconds or minutes the watch gains over 24 hours and whether the error is consistent. A vague “fast” and a repeatable +90 seconds/day are very different diagnostic inputs.
Magnetism can produce dramatic gains
Mechanical watches can become magnetized in ordinary life. That possibility should be considered before assuming the watch needs a full overhaul.
Regulation is not service
Moving the regulator changes rate; it does not clean dried lubricant, restore amplitude or fix wear. If the movement condition is poor, chasing rate can hide the underlying issue.
Send the pattern
Tell us whether the problem was gradual or sudden, whether the watch was dropped or exposed to magnets and how it behaves at different states of wind.