I try to do everything with strict form but ...
I think it's a bit extreme to say "never cheat".
For instance ... I think you need to use progressively heavier weight to both get stronger and grow. Sometimes - if I hit a plateau - I'll intentionally "cheat" in order to use more weight on a movement.
For instance ... I have no problems using a tiny bit of "body english" on the upward movement of DB flies if I'm maxing out on the weight. I know what my max weight is for a strict movement - and I only use the "english" if I go above that.
I find this helps me to get over some plateaus - it's one technique that works for me anyway.
i do the same thing with squats - I'll load the bar up with an impossible weight that I know I can't squat - and I'll just pick it up off the bar and hold it for a few minutes upright. It's always funny - cuz I'm an old guy and when the younger guys around me see me loading the BB for this - they become alarmed! "That old man can't be crazy enough to try to squat that!!??"
I just laugh at them when I put the bar down and say ... "hehe - you thought I was gonna squat that didn't you?"
But I find that just picking up and holding a weight that I know I'm not ready to squat helps me get over a huge hurdle - and that is a psychological one - that I CAN pick up the weight - and eventually - I'll be able to lower and lift it too!