The back is the largest flat area you have, which is why full back pieces are often the work artists are proudest of. It suits large scenes: a dragon, a phoenix, a landscape, a pair of wings across the shoulder blades. Smaller pieces work too, especially along the spine or between the shoulder blades, where a vertical design follows the body's centerline.
Back skin is thick and mostly covered by clothes, so tattoos there age well. Detail holds, blacks stay dark, and colors fade more slowly than on arms or hands. The lower back can stretch with weight changes, and the area over the shoulder blades moves a lot, but a good design allows for both.
Visibility is low. A shirt covers almost every back tattoo, and only open-backed clothes or swimwear show it, which makes it a safe choice for any job. The trade-off is that you will rarely see it yourself without a mirror, so it pays to love the design rather than want to look at it every day.
Healing is manageable but awkward because you cannot reach most of it. Ask someone to help wash and moisturize it, wear loose shirts, and sleep on your front or side for the first nights. Large back pieces are done over several sessions, so you will heal more than once.