Like Chayro, my upgrades stopped when the money ran out, or rather, I retired. You can always improve on a system, but if you have chosen wisely, then I believe in the old rule, that you need to double the cost of a component, to really improve the sound. A little very basic maths tells you, that soon gets very expensive.
A general guide is, that you can go to a show and all but the uber expensive rooms, sound worse or no better than your gear. At a recent show with Wilson Alexias and D'Agostino Pre and monoblocks, sure I could clearly see what I was missing.
Secondly, do you count a day not hearing some music on your setup, as a day wasted somehow. My 2 cents worth