Where to invest

Come to think of it. It is an investment in mental and emotional health.

.....You're spending the money...not investing it. Any money spent in audio is gone forever.....

I have gone through 5 pairs of speakers over the last decade, and never lost a penny on resale. Same is true for a host of other gear. Of course, you will depreciate on the latest greatest digital stuff, but all things analog can be owned virtually free. So, while "investing money in audio" it is not quite, for me the appropriate term would be to "tie up money in audio".