If you're doing barbell squats etc. get a lifting belt, as I get older this REALLY helps with the back, and in turn squats really help with the back. Had "a bad back" since I was a teenager, lifting weights is one of the few things that helps.
A cheap Amazon one seems to be OK (Got one for my Son) for about $60 - $70 I'd recommend a 10mm lever belt (Might have to search for Powerlifting belt). Nylon/velcro one suck and anything with a taper / weird shape just indicates people don't know how lifting belt actually work. Single prong ones might be good too, I've only used lever belt (Convenient). Takes a little bit to get used to and you'll get some nice red marks or even bruises etc.
When I was younger I only used it for working sets, now I use it for heavier warmups etc. (And bench and overhead press)