The actual toilet itself, the bowl and tank, are built to last for an indeterminate number of years. In older homes, you will often find an old model toilet that still works. Although the fixture itself will remain in good condition with proper maintenance performed on it, the nuts and bolts of the toilet, along with the flush system's working parts, do wear out.
Helping the Toilet Last
Outside of cosmetic reasons, such as color and one-piece versus two-piece models, the only reason to replace a toilet is if the fixture is broken while being installed or moved so that inner parts can be repaired. Protect against this type of damage by always setting the toilet on a towel or newspaper to protect the fixture from a hard floor. Also, do not overtighten the nuts on the closet bolts in the toilet base or the nuts that anchor the tank-to-bowl bolts.
Tank Parts That Wear Out
The components of the tank's flush system, comprised of the flush valve assembly and the fill valve in gravity toilets, are the parts that are often the culprit behind toilet problems. These parts are usually made of plastic or rubber and do wear out and need to be replaced or cleaned. When the toilet phantom flushes or runs constantly, the villain behind it is one of these parts. One part in particular that often deteriorates inside the tank is the rubber flapper that opens and closes to let water out of the tank and then seal it in.
Parts Underneath the Toilet
A leak that seeps out from underneath the toilet does not mean the toilet itself is worn out. A wax ring is installed underneath the toilet, providing a seal against water and sewer gases. When this wax ring wears out, you get the leak from underneath the fixture. Simply replace the wax ring. Also, if the toilet rocks, the problem is often a damaged flange, uneven floor or possibly a faulty wax ring again. Repair any of these components and the toilet usually sits evenly.
If left without regular maintenance, the toilet bowl can exhibit weak flushes, which doesn't mean the toilet is worn out. The flushing power is weakened when, over time, mineral deposits clog the rim holes underneath the lip of the bowl, impeding water flow from the tank to the bowl. The clogs can be cleaned out by placing tape over the rim holes and pouring vinegar down the tank's overflow tube. Let the vinegar sit overnight. Clean out the holes using the end of a straightened-out wire hanger. Also, maintain a regular schedule for cleaning out the bowl and the toilet's outside surface. This keeps the appearance of even an old toilet appealing.