PPR
A little while ago in CHIRP there was a whine by somebody who hadn't phoned for PPR and found on arrival that the airfield was closed for 30 minutes during the day for an aerobatic display. Being a pilot he was outraged by their actions...
If I'm going for a bimble to somewhere I know and I either have alternate destinations or don't mind just flying back then I may not phone first*. If I really want to land there, or I need to get fuel then I'll ring before I take off.
Dave
* only applies to airfields - I always phone strips.