It seems like my AC feels cold at times and other times it feels barely cool...especially on hotter days. Is it my imagination or the AC system is fluctuating in performance?

Does the AC system needs refill after so many years? Since 1999, I have never had the AC system refilled.
My understanding is that if the system is NOT leaking, then there is no need for refill.

Thanks for any feedback.

 

of systems leak a few % a year.
Run the a/c onboard diagnostics values 1-8 and any errors
Post them.
Easy to solve once the numbers are seen.