Many better tripods are sold as legs-only so you can choose the head separately. That matters because tripod legs and heads serve different needs, and there isn’t one head style that works best for everyone.

The key practical point is matching capacity: the head and legs should both support your camera/lens setup. Beyond that, the best combination depends on how you shoot.

Tripod heads vary a lot more than legs. Different heads offer different strengths in speed, precision, motion control, and balance. For example, a 3-way pan/tilt head may suit careful, controlled adjustments, while a ball head is often preferred for faster positioning.

So the choice is partly functional and partly personal preference. Your subject matter, working style, and ease-of-use preferences all affect which head feels right.

Selling legs and heads separately also helps photographers who already own one or more heads and don’t want to buy another unnecessarily.