I rent a 100' electric power rooter about once every year or two and do both my outdoor deck drains (usually root problems) and my house main line (usually kitchen waste buildup). I have stopped using chemicals except to deal with one non-accessable u trap in the laundry room.
Like i said earlier, I'm still a fan of the old fashion manual coil type snake for anything of more significance than some hair in the tub. Never used one of the auto feed ones, but they are probably more hassle than it's worth when they hit a tricky spot that takes some work to get past.
on my parent's house every 6 months or so.
If it doesnt work, then go with a physical snake.
I don't have problems with clogs but the overflow paths get smelly. On a plumbing forum someone mentioned using an enzyme cleaner. Is Naturall an enzyme cleaner? To let bleach or Oxyclean sit in the overflow path I have to rig up a balloon in the drain so I can fill only the overflow path.
"A pen in the hand of this president is far more dangerous than a gun in the hands of 200 million law-abiding citizens."
A word of caution regarding these chemicals. Yes, most are harsh enough to eat through the ABS or PVC drain pipes, but another thing to consider is that if you have a septic system installed vs. a main drain to a city sewer system, the chemicals will throw off the natural enzymes which break down your waste, and this in itself will create bigger problems down the road.