Depends on what you use.
*Waxing takes a layer of your skin and let's be honest it hurts a lot!
*Thread is best for eyebrows and upper lip.
*Shave is the safest and painless, but you cold be irritated and the hair comes out like thorns.
I personally used to wax my bikini, but I got my ehem...parts lasered with a laser treatment, costly but sooo worth it!!. For the rest of my body (legs, pits, etc) I use an EMJOI OPTIMA hair remover. This device plucks the hair at high speed, you almost don't feel anything... and you will be hair free for weeks. Here's the link:
I used to wax my legs but I had too many ingrown hairs so now I just shave. I shave my bikini area and still wax my underarm hair every so often and, I know it sounds weird, but I pluck in between waxings.
I've had electrolysis on my belly button area - it really works but takes FOREVER and HURTS (it's taken about two years of doing my belly area to get happy results... ugh).
MISHIMOO: I would love to get laser but I'm really torn on if it'll be a waste of money or not. My bikini hair is dark but my underarm hair is a bit lighter and sparser and my leg hair is lighter as well... Any tips??