Our new home has only one bathroom. After 1 week I was at the hardware store buying a plunger. I’ve had to use it once a week since. This is not good. We personally know better than to flush anything other than TP, but that doesn’t mean the prior residents respected that rule. Still, I did some searching and analysis, and as stated below, older, low-flow toilets tend to have this problem. Ours is most certainly low flow. It looks like I’m just going to have to replace the whole darn thing. If you’re having similar issues, this is a sound diagnostic article.
A constantly clogging toilet can only be attributed to one of the things mentioned in the link below.