Pros makes the outfit look proper, dont jiggle around, give you a nice shape if you're wearing a low cut top, its always nice to wear a lacy one and let the strap up on your shoulder leave the rest to imagination ;)
Cons- more uncomfortable then braless, struggle when straps fall down if you havnt adjusted them, getting fitted is annoying, boobs change before and during periods.
I have a bra on 98% of the time. Sleep with them on too. It's honestly uncomfortable for me not to wear one and having boobs that aren't exactly small, I can't go out in public without wearing one either. Not that I'd want to lol