We've got a lot of iron in our well water. I've had two problems with the toilet due to rust.

One is that some styles of the cylindrical-type floats have accumulated enough of the rusty powder that the float would occasionally get stuck. Shaking the float vigorously up and down will free it up for a while, but there has been no problem with older float-ball style.

The more serious problem is that it seems like the rim of our current toilet has gotten clogged with rust, causing the bowl to fill too slowly for a good flush. The previous toilet in this house never had that problem, but maybe this one has especially small holes at the rim.

We are presently renovating the bathroom, so the toilet is being replaced in a few days. The new toilet is a nice Kohler toilet, and if it started flushing slowly, I would definitely try a rust remover. My understanding is that having cleansers in the tank constantly can degrade the rubber parts, so the tabs you keep in the tank are a problem but cleaning it every few months would be fine. I just wouldn't let it sit in the tank for more than a few minutes.

But if you are getting rust deposits in the toilet, also keep an eye on the clothes washer. Every year or two ours starts to fill slowly, and I need to take the hoses off and clean or replace the part where the water goes in.

You might consider some kind of secondary filter. I've got a two-stage filter (no softener), but I'll be adding another one once the bathroom is done.

You'll need to drain the water heater every so often also.

some have suggested elsewhere on forums such as this that excess mineral deposits on the fill and flush mechanism might eventually cause "clatter" when the toilet is flushed.