I've had cats for donkeys years and have always given them a collar. The collar usually had an ID tag on so, if the cat got lost or injured, people would know where to take her. I now have 5 month old kittens and they are regularly going outdoors so I bought them new collars yesterday. Boy cat loathes his and last night managed to drag it in his mouth and I think cut his mouth a bit in the process. We removed it and tried again this morning with the same result. Both cats are microchipped so does he really need a collar? I always think a collar tells people a cat is not a stray but I can't risk him injuring himself.