Why are sewer clean-outs so tight to work with?

Having enough room to work on a sewer line is extremely important. Especially to get the job done properly. Tree roots are not easy to remove from sewer lines with limited space to work in. Running sewer lines over 100ft. are also challenging if working in a small tight space.Don't cover up clean-outs and make sure that access panels are much bigger meaning wider then the one in the picture below.