Cleaning a PCP air rifle.

I have an Air Arms 510 that is right around 10 years old. I have used it mainly for pest control, and my round count through it is probably less than 1000. I have never cleaned it since I bought it new. Recently I had to have the seals replaced because of a leakage. It is like new now. The accuracy of this thing has been very very good. I am able to group 5 shots in 50 yards into a 1 inch group for the most part. Like I said I have never cleaned the rifle till yesterday.

My question is...After how many rounds should you start to consider cleaning the rifle? Now I know if my accuracy is suffering, this should be the first thing you should consider.

I cleaned this rifle and removed very little fouling. I want to keep my rifles in tip top shape. So maybe should I just keep shooting till I start to see the accuracy start to suffer?

Thank you all...