This is known as "the gunslinger hypothesis". No matter how fast you are, there's always someone just a little faster. In speaker terms, there is always something newer, better, just a little less/more expensive.
I've also been guilty of upgrading like this, but have decided to stop. Maybe in 5-10 years I'll need something to replace my "old" Sierra. If I can still hear at that time! (Yes, Mr. Neato, I know you're joking. As I am.)
Pegleg