I introduced Tessa to the bell when I first got her at 10wks old. I made her hit it with her paw everytime I put her outside and after about a month, she started doing it on her own. Tessa has since "taught" Harley to use it, and now my cat will also use it. FYI my cat is 6yrs old and saw that the dogs got to go out when they ran it so she started to use it too!