My cats are rather unusual, while they are indoor cats I do take them outside only on a leash (all of the big cats are leash trained to some extent, some better than others) or out to the cat enclosure. I also take Pooky for bike rides, to the pet store (basically Pooky just likes to go anywhere, him and Dusty both like to ride on the golf cart.

The only time mine wear collars is when they step anywhere outside the door, even if it's inside a carrier. However I can't buy cat collars because of the 'quick release' feature. Since I walk them on a leash like a dog, I have to buy small dog collars for them. I don't use a harness because several can get out of any type of harness I put on them, no matter how snug, and Dusty will refuse to walk with anything around her middle or back.

I've always used a stretched out hair scrunchie as a training collar in the house until I could work my way up to a break away collar, then finally to a dog collar with the leash.