In my .243 safe max is 2.037, so when cases reach this length I trim them back to 2.033". DO NOT try to load and fire a round when the case length is making the bolt difficult to close!
In my opinion there is no significance to cases being a few thou shorter than the SAAMI spec of 2.035" - it is not going to make a big difference to accuracy. But if you trim them very short, obviously the case to bullet tension/friction is reduced or you will not be holding the bullet stable which is not a good idea. The important thing is to check case length after re-sizing and when you need to trim again, make them all the same!