You know, the small things that can save you a lot of money. I’ll start:
You can get “hospital” powercables that are completely shielded for 20 bucks or so.
You can get anti vibration pucks for washing machines instead of spending 10 times that on the same product which is just labeled as “speaker pucks” instead.
Make sure you have optimized your setup and room each time before you upgrade gear and again after any upgrade. Change only one thing at a time, and slowly, so that you can do this properly.
When you decide you want to buy something, wait six months and see if your priority changes during that time.
Listen to the music and try not to listen to the equipment. Make improvements only to the extent they help you enjoy the music more and not just because the equipment sounds better.
Do not buy new gear unless you have auditioned it at home first. Used, different story.
Some of these i might have tried to say, but you said it better!
Let me add - try really hard NOT to buy ANYTHING.
And - When you DO buy something get what you really want, or get something BETTER than what you really want. Don’t move up incrementally because this just causes more purchasing events.
That last bit is important. In fact I avoid A/B testing generally because I think if an improvement is slight enough I need to go back and forth, it isn’t worth spending money on. Any upgrade should be a night-and-day difference for the price of gear.