There isn’t one perfect rule, but for camera bodies prices generally trend downward over time rather than up.

A good value point is often when the replacement model is announced or released: the outgoing body may be discounted, and the used market can improve as upgraders sell theirs.

That said, if this is your first serious camera, waiting only to save a little money may not be worth it. The time spent learning exposure, focus, and technique is usually more valuable than a modest future price drop. If you need the camera for a trip or project, buy it about a month early so you have time to learn it before you rely on it.

So the practical answer is:

• If lowest price matters most, wait for the next model cycle or shop used.
• If you need a camera now or are just getting started, buy when it fits your needs and start shooting.

Also, lenses often hold value better than bodies and may even rise in price over the years, so investing in good glass earlier can make sense.