The inner wrist is small, flat and faces you, which makes it a natural home for a short word, a date, an initial or a small symbol. The outer wrist takes slightly larger pieces, and a band that wraps all the way around reads like a bracelet. Designs that follow the wrist's width, rather than running up the arm, tend to look most deliberate.
Wrist skin is thin and sees constant movement, sun and friction from watches, bracelets and desks. Tattoos there age better than on hands or fingers, but very fine lines and tiny text can soften and spread over the years. Lines a little heavier than the thinnest you can get, and sunscreen once healed, keep it crisp.
A wrist tattoo is visible whenever your sleeves ride up, and the inner wrist shows every time you reach for something. A watch, a few bracelets or a long cuff will cover a small piece, so it is easier to manage at work than a hand tattoo.
Healing is quick for small pieces. Keep your watch and bracelets off for the first couple of weeks, avoid resting the fresh tattoo on a desk or laptop edge, and keep it out of long soaks while the surface heals.