seems there are different etiquettes at different locations /Too many rules for the average Joe
Not really "rules" IMO, as much as musicians having to concentrate a bit after all. A movement is not an intermission, it's part of a piece of music, so clapping whenever, basically there's some silence, is disruptive. Of course it's also nice for musicians to experience audience appreciation....
OTOH, as noted above, in some cases it's tricky to recognise the end of an obscure piece. At one premiere public performance I went to, the Hall had stationed an elderly gentleman in one of the front rows who was obviously familiar with the piece and, amazingly, everyone in the audience followed his clapping cue (hesitantly at first, of course). Or, I think they had deliberately stationed him -- maybe he is composer's family.
A simple thing to do is read the programme. It tells you the movements -- and the number.