Probably most of us have that same concern to some degree.
Perhaps rather than trying to change out your equipment on a regular basis, you could switch to either:
A). Trying out different music from different genres.
(i.e. if you're into jazz, try classical or visa versa.
Or, even if you're only into rock, try different sub-catagories, like alternative rock, or heavy metal. (This is currently what I am trying to do to kick the upgrade habit! It is somewhat working, as I have at least slowed down! :-) )
B). Or, if you're into vinyl, like I am, you could try to either get better pressings of albums you already have, or better yet, get vinyl copies of albums you only had CDs of.
Both of these alternatives still involve spending money, but this is a hobby after all. (And at least the law of diminishing returns does not play into it as much, except for getting the best pressing alternative, which is starting to get a little bit expensive! However, IMHO, that is almost an investment, as the price of good pressings seems to be rising pretty constantly. I honestly feel I have made money on my good or rare pressings, should I feel the need to sell them.)
My two cents worth.
