I got a buzz cut for the hot weather and I like it so I think I'll keep it from now on. I get a number 4 on top and 3 on the sides. How often should I get it trimmed to keep it looking neat?

It depends on how fast your hair grows out. When it doesn't look as nice and neat anymore, head back to the barber. My hubby and the kids go every 3-4 weeks.