I've never played D&D and I'm getting into BG3. I must be marathoning my characters cause I'm usually out of spells when I run into fights. My useful exploration spells also cost spell slots so I'm usually proceeding with cantrips for my adventures until I decide I really need to recharge.
How often is everyone else going through a long rest? I know there's a trade off of consuming camp supplies and so maybe I'm just the guy who saves all the items for end game and never ends up using them.
You should be long resting all the time. There's not really any penalty to it. Hell, if anything not resting runs the risk of missing out on important NPC conversations.
Camp supplies are never a problem. I end up selling a lot of them - particularly the heavier and more valuable ones (we only drink cheap alcohol at my camp lol).
There are certain timed events that will trigger if you long rest nearby, so make sure if you’re near a place that looks like it needs immediate attention, that you don’t long rest quite yet.
Yes, for example if you see a group in a fight, then go long rest, when you come back the fight will be over.
One thing I'll add is that Find Familiar doesn't seem to refresh on long rests (not for me, although I haven't checked in the latest patch). So if you have any short rests left it might be an idea to use one of those then long rest.