It is possible to convince oneself that not buying stuff is better than to do it. I mean this not in a superficial sense like thinking of a good argument why it would be better to refrain from a purchase, but in the deeper sense of mentally exercising to get off the hedonic treadmill. Letting the brain's reward respose trigger not by clicking "Buy" on that webshop, but just before, and then closing that browser tab, happily avoiding another thing that might have been nice to have, but ultimately neither necessary nor fulfilling.

Related to that, I find that renovating and repairing things can be very rewading as well. The shoe rack or the table start to look shabby? Give them a new layer of paint! It probably takes less time than finding a replacement anyway. Get a sewing machine! They are a truly ingenious invention. Those dog toys or clothes for exercising need not be pretty, just functional.

Most important I find the insight that, sure, there are newer better nicer versions of anything that you have, but it is liberating not having to think about the next new thing, as long as the old one does the job and is good enough. My six year old laptop is quite beat-up by now and will not make it that much longer, but it is still fully functional and I am happily pushing the environmental and mental burdens of replacing it further into the future.