As a gamer I've fallen into upgrading my CPU/mobo/ram and GPU in an alternating fashion every 2ish years.
I might break the pattern this year though, I got a 3900x last year around launch and moved my 4670k to a home server. I've been pretty impressed with the 3900x while the 4670k has been maxing out all cores in the server for some tasks so was considering buying a second 3900X(T) to replace the 4670k again. But with the rumours about the 5900X, I might end up putting the 5900X in my desktop at the same time as a 3000 series GPU and moving the 3900x to my home server.