Sudden multiple accuracy changes

[Slurve30]

What would cause a consistently running watch to have a change in accuracy?

I had my 16570 serviced in December, and it came back running at +1s/day consistently. About four months, it suddenly started running at +5s/day consistently. After about two months, it then started running at -0.5s/day consistently which is where it is at right now. (I'm happy with all the above rates, even when it was at +5s).

Any idea as to why I would see multiple shifts in accuracy? Watch is worn daily about 12 hours, and almost never wound. Watch has not been opened since service and as far as I know, not subjected to any major shocks or magnetic fields. Curious to know what causes this or if this is just how mechanical watches sometimes act.

[schoolboy]

I don’t know if it would affect it that bad, but one thing to consider is the way you lay the watch down at night.

If you have changed the way you lay it down, that could be it.

For example, dial up would speed it up more than it being on the case side, with say, the crown up.

[GradyPhilpott]

+5/-.5 is pretty damn good and as noted above, something as simple as how you lay the watch down at night could account for the difference.