Just like the title says. Im 35m (ftm, new to being seen as a dude.), and look "anywhere between 18 and 40, I have no idea." according to my friends.
I work with older guys, 55+, some of them occasionally call me bud or buddy. Im not sure how they interact with other people.
When out in public, strangers seem to address me as such too. "What can I get you, bud?" at the deli counter.
I dont ever call people this. Im definitely more or a "dude, bro" kind of guy.
Im guessing its really a matter of how it's said. I just cant imagine someone calling my dad bud? I dont know.