Kind of a flipped version of this thread, I guess, but from another angle
What have you learned from personal experience to never buy cheap?
The first thing that comes to mind for me is hard drives. Made that mistake once. Within 6 months I’d ended up buying a more expensive one anyway because the first one was making odd noises and I didn’t trust it to not lose all my files.
Tattoos is another obvious one. I’m sure there are some decent artists who don’t charge much out there, but I’ve seen enough bad tattoos in my life to know that you really do get what you pay for in that respect.