I don't know how you could determine when a good time is.
It depends on far too many factors.
In Washington, we leave the caulking off at the back of the bowl, so we know sooner if there is a leak.
I would like to know how often if ever you need to change the wax rings on your toliets other than when you remove them? We ended up having water come through our ceiling from an upstairs bathroom and now the plumber is trying to say that we should have changed the wax ring before now. Is this true?
They are trying to say that the repairs are our responsiblity, even though the home is less than 8 years old. They are trying to say that it is a normal maintance item that everyone should do every 3 to 4 years. Since nobody I know has ever heard this, I was just wondering if it was true, or if they are just trying to pull something over on us because they didn't install our toilet correctly. My husband saw when they took the toilet off, that the flange sat about 1/2 below the floor level, and my dad said that it is supposed to sit above the floor level, or else they have to use two wax rings to seal it.
Who is correct?
A properly installed toilet should never need the wax ring replaced unless it is removed for some reason. If the toilet rocks in the slightest, it is not installed properly, and it could fail minutes after installation.
Wax doesn't leak away (a rare exeption might be if hot water ran down the toilet long enough to melt it or there is a heater right behind the toilet, making the whole thing hot). It won't repair itself, though, and doesn't rebound, so if it gets squeezed too thin, then the toilet rocks the other way, it often won't stretch back, so the seal is broken.
A wax ring isn't like a rubber washer in a faucet. He doesn't have any science to back him up...make him show you something from a reputable source that says you need to change your wax ring on a periodic schedule...he can't.
A wax ring can fail if the toilet rocks, it is aggressively plunged (blow out), or too much heat, and it melts. Other than that, it should be good.
Important note - I'm not a pro
Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014