Is it always better to just buy now and ignore marketing hype, announcements, and speculation? If I always wait for the next model, I will never buy anything.

What about buying the cheapest thing now as a stop-gap, and waiting until after the next big photo-show? Or renting equipment until I find something I really like working with? (Won't that get expensive over time?)

What do you do when you want to get new kit?

I would really like to hear how best to make the decision to buy or to wait.