How long do I leave the prong collar on for? is a question that I get in my email often.

What you don't do is leave it on

1)24 hours a day

2) when in a crate

3)when off leash running around

4) when not supervised

5)on a tie out in your yard

6)when swimming

7) if playing with another dog

You should use it for training, training just about everything as well, if your dog has a leash on why not have it attached it to a collar that you can have a great conversation with.