Sakin, unless you start to smell something funky, don't bother... If it ain't broke, don't touch it... With our past 2 cars, the more we get "cautious" with cleaning, baklas, kabit, refill oil/freon, etc... nagkakaroon ng ibang prob sa system hehe. Samantalang mga cars ng parents ko dati we never had them cleaned, they lasted over 10 years before we experienced any AC related probs.