I was the favorite person for one of my family’s cats. I moved out, and started medically transitioning about a year later. I would only come by about once per month, and he very clearly still knew it was me. He lived for about 2 years into my transition (he was like 18 when he died), and I remained his favorite person the whole time. So while they might notice changes, they can (at least sometimes) still tell it’s you!