Mine gets wavy and starts to curl after about 4". When it was long I'd shower at night, tie it back in a ponytail and put another rubber band every 2" (just snug, not tight). When I'd wake up it would be straight and dry.
I've been buzzing it down with no attachment for well over 10 years. Easy hairstyle. I need to start using the #1 attachment though. I have a full head of hair still, no bald spot and my hairline is still in a good place. Might as well show it off while I can!