You know, when you move into a new home, you really don't know how the previous owners took care of the pipes. In our case, we suffered from standing water in our bathroom. We tried several liquid drain cleaners for over a year, where it had temporary fixes. We had a enough pouring our money down the drain, so we reached out to Advanced Plumbing.
Two gentlemen came over and snaked the drain. Interesting enough, NOTHING came back, no hair, etc. What they did was provided an education on small pipes, pipe/elbow build-up. They were able to push the build-up all out.
Liquid drain cleaners only fix the first few feet, but your pipes extend farther than that and there could be build up in every elbow leading to the sewer system.
It has been nearly 8 months since we invited Advanced Plumbing to our home to fix the standing water and it has been clear ever since!