Mitch4t,
First of all, congrats on having been born in the best year of the last century. You are in distinguished company.
I think many of us as we approach retirement undergo the same sort of analysis. In some respects it is a farewell to higher income living, and a reflection on what our values are. I began about 7 years ago making a list of what remained to be accomplished in order to provide for retirement as I envision it. Music, of course, is a major and essential component of what I do with my now precious free time. That will surely continue when I have more time. Accordingly, I have nearly completely revamped my entire rig over the last two years. All of this was well planned in advance, and I am almost finished. My system as it is currently configured is good enough that I can live with it with no further improvements, and do so with no regrets. However, if, seven years from now, I have an opportunity (and money) to substantially upgrade, there is little doubt I will do so.
So, the answer to your question is this--- Stop upgrading when you lose interest or run out of money. Meanwhile, enjoy.