Just looking at some pics from a recent shoot, and was disturbed to discover that a surprising number were a little out of focus.
Further checking revealed that they were all with the same lens - but shots with other lenses were fine. Damn, problem with the lens ... which was working fine last time I used it.
Then I thought maybe it needs re-calibrating with micro-focus adjustment. That's when I discovered my previously stored adjustments had disappeared (the lens in question required -10).
The explanation was simple - I'd had the body serviced, and clearly Canon had reset everything to factory defaults. Now while I picked up on the obvious often used settings, I'd completely forgot about the micro adjust - its not like you use it everyday.
Anyway, just a heads up which may save someone else some head scratching!