I had a martial arts school and one of my partners was a cop. He showed me a video called “Edged Weapons” and in that video a safe distance from someone with a knife, with your gun still in the holster is 21 feet. And they show you with someone holding a rubber knife at 5 ft., 10 ft., 15 ft., 20 ft., and they all get stabbed. 21 feet was the safe distance from someone who knows how to handle a knife.
You got it. For pepper spray it’s 25 feet because it takes longer to act. The good thing, however, about pepper spray is if you have any doubt at all, you can just hit them and say ‘sorry’ later.
And it is only good as a delaying tactic. The move after deploying pepper spray is to run and call 911.