Clogs are to be avoided at all cost, but to be honest in 15 years I've not had one...at least not in the pipes. I have had a few ports clog with long splinters and such. I didn't add clean outs, but I do have a section that's set up as a slip joint for easy dis assembly (one piece slides far enough into another to break the line). That is there more for ease of modification than cleaning. Personally I wouldn't worry about clean outs.