Start? Not sure there is a specified date. I 'bought' another one last week.
Stop? Usually when I lose mine. They don't stay in button holes too long for some reason.
Maybe I should just get one for the car(s).

Graham (G4FUJ)

Sold L44FOR 4/4 Giallo Fly
'11 MINI Countryman Cooper D All4
'90 LR 90 SW