Ageing myself but in 40+ years of dog ownership and working professionally with dogs I have never ever had a dog
slip their collar
lead break
or escape from a harness
Risk assess the situation and use appropriate leads and collars/harnesses for the dog in front of you.
I often work with aggressive dogs and dogs needing rehabilitation and again in this situation breakages has just not been an issue.
However I had been observing an ecollar training session where the ecollar skim button got stuck on and the dog had a constant zap for over a minute whilst the trainer struggled to get the battery out of the remote control.......