Fair enough on the personal decision part. I'm less interested in telling people what to do and more interested in whether the premise ('nicer things = happier') actually tracks with how human satisfaction works. The research suggests it often doesn't, which seems worth knowing regardless of what you choose to do with that information. [1]

1. https://pubmed.ncbi.nlm.nih.gov/690806/

It's a bit more than just a personal decision. Overconsumption is ruining our environment, which we collectively have to share.