I have my cats microchipped and they also have collars w/tags. The collars are breakaway collars so they could easily come off and the microchip is just an extra precaution if they are ever lost. My cats are indoor only, however you never know when a fire, other natural disaster that could ruin your home and they could get out. It may be an extra expense, however it's one I am willing to make to get my family back.