Only two of our six boys still keep their collars on; our two youngest. We started each of them off with collars (bells and bling to boot!) but mostly just to find them as the little fellas do get lost behind furniture and large appliances! The older ones have somehow gotten them off and gave us complaints about trying them back on again. The small guys seem to love their jingles and diamond paws and hearts. They are all indoor-only cats with tons of lovely windows to perch themselves at.