so ive been licensed for about 4 months now and still trying to figure out the etiquette around phonetics. like my callsign has some letters in it that are pretty easy to understand over a clean signal but i see some guys on the local repeater spelling out their whole call phonetically every single time they ID and others just say it normally. is there like an actual rule about this or is it just personal preference? i dont want to sound weird either way. also does it matter more on HF vs VHF because the signals are so different

No hard rule says you have to use phonetics every time, its more of a judgement call. On a clear local repeater with a good signal most people just say their call normally and thats fine. Where phonetics really matter is on HF especially when the band is noisy or youre working someone far away who might not catch every letter - that's when NATO phonetics earn their keep. I'd say get comfortable using them though because when you do need them you dont want to be fumbling around trying to remember if its Foxtrot or Fox or whatever. Some guys also use phonetics out of habit which honestly isnt a bad habit to have.

yeah on 2m i almost never bother unless the signal is rough or im trying to work somebody whos clearly not copying me well. but the one time i forgot my phonetics on 40m during a pileup i ended up saying something like "K for... uh... Kite" which was embarrassing lol. just practice them until they're automatic. also some DX stations will specifically ask you to say your call phonetically so you kinda need to have them ready anyway