It's hard to imagine that as little as ten years ago, lifters really couldn't analyze their technique in real-time. Generations past had it even tougher. If you weren't in the physical presence of a coach, it was nearly impossible to get outside feedback on your lifting.
Nowadays virtually everyone carries around a smartphone: a video camera in your pocket. Asking a stranger to film you at the gym is awkward and annoying, and I've spent way too much time out of my workouts trying to figure out how to prop up my phone on some adjacent piece of equipment. I picked up a telescoping tripod from Target a few weeks ago, and it was a smart decision. For 12 bucks I now have perfect footage of all my heavy attempts that I can analyze, or email off to a lifting partner or coach for feedback.