I really struggle with this issue. I have a cat that has Feline Herpes which manifests itself as conjunctivitis and URI. She's now 4 and every single time she's gotten the FVRCP (or whatever those letters are) booster, she's gotten an URI within 2 weeks. It then takes 6-8 weeks for her to get over that.So, I've decided that she's NEVER going to get the FVRCP shot again, unless they take out the FVR part. She's also susceptible to the "C" part of the shot, the calicivirus, which is another reason why she won't be getting that shot. The last time she had a rabies shot, which was 2 years ago, she developed a mass at the injection site. It's not bad, but now I'm worrying she's got some kind of carcinoma at the injection site. Since she's not had shots in a year, she's been the healthiest since we got her! This year, she'll go have at least a rabies shot and I'm debating whether to get the 3 year or the 1 year.
My other cat has kidney problems, arthritis, and is at least 13 years old. She's had shots almost every year that I've had her. A couple of years ago, I opted to not give her the FVRCP shot, just the rabies. Goodness! I've never heard such outcry from the vet's office and I've been taking her there for at least 6 or 7 years, so they know I'm a good pet parent! I explained to them that she's not at much risk, she's had the shot every year since I've had her (11 yrs) and that she's in good health. She NEVER goes outside and she's not exposed to other cats. I also explained to them that she probably still has enough of the vaccine from the previous years in her system that she was in good shape. So, for the past 2 years she's not gotten the FVRCP. This past February, she got the 3-yr. rabies. She's due again for her annual check up in a couple of months where she will NOT have ANY shots and she'll get her blood drawn to check her kidneys. She'll also have the cataract on her eye checked out, which we've been monitoring the past 4 years.
All of this to say, it depends on the cat and discuss it with the vet.