Clips should be used for two circumstances: A brand new weightlifter and a power lifter whose bar bends from the amount of weight they’re lifting which causes the plates to slide down and off.

Any other situation, they do more harm than good. They contribute to muscle imbalances because normally the weights would slide off on the weaker side. Once you notice this happening, you readjust accordingly. With clips on, you have no idea which side is lifting more and you start forming crazy imbalances. I’ve never seen someone drop weight plates from it being not clipped, but I’ve definitely seen people almost get hurt doing several exercises because they couldn’t shift the weight off the bar. Anecdotal, but it’s been 10 years of lifting through high school gyms, city gyms, and 3 different gyms at a very large state college. That’s quite a sample size I’d say.

If you don’t believe me, go take a bar and clip the weights to it. Let’s choose barbell lunges for the example. Then consciously allow the bar to dip on one side of your shoulders. See how you’re still able to perform the lift without the weights falling off? Wow! Must be doing the exercise correctly then. Except you aren’t.