I think the difference between “luxury” and not is a red herring here. The real wisdom is to spend enough to get really serviceable versions of the things you use everyday. That doesn’t mean “luxury”, per se. but it does mean if you e.g. spend 6+ a day in a chair at your home (or work) , make sure it’s a good fit for you.

Get a decent mattress and pillows. Replace your pot from college with the handle that falls off. Paint the room you hate the color of. The ROI on such things is huge.