I agree with the having it some place you can hide it! Mines very low on my back, so some bathing suits even cover it. I ussually wear low rise jeans, but it's easy to hide when I need to.
Most people I know don't know that I have it, it's something very personal to me. I got it for me, not to show off or be trendy!
Mine took about 15 minutes, halfway through I got dizzy, then sick, they got me some soda and after that, it actually tickled!!!
Make sure they do a stencil on you first to check positioning/size...
My friend Kerri got one from a not-so-great place-they made it a LOT bigger than she wanted and the guy obviously wasnt very good because he told her he "Couldn't make it any smaller or the colors will bleed". Well, my brother got an EXTREMELY intricate pin-up girl on his leg with a LOT of color and very SMALL details...no bleeding...I think the guys was inexperienced. Do your research, if you can talk to people who have gone there, DO! and ask to see pictures!