It seems at my place that once or twice a year, the back toilet will become a temporarily slightly clogged. The flush fills up the bowl with a suspicious amount of water, and empties more slowly than usual. And it becomes a battle of wits: should I call in the plumber (with his special machine) again or hope the problem goes away before anything overflows?
My natural procrastinating stance usually results in the latter. And it does go away by itself. The tree-roots or whatever is down there will clear, and it’s back to normal. When I asked the plumber about it, he basically said there’s no easy permanent fix to this — only a complicated/expensive fix.
One day earlier this year it spontaneously cleared itself like this while I was sitting on the can. It did so with quite a loud gurgling blurping noise which for a split second left me most alarmed as to the state of my bowels.
But no, all was well, and the toilet once more was flushing with the best of them.