Two days -two loos.

We have lived in our house for nearly 15 years. It is over 15 years old and I walked past it many times on my way to work while it was being built. In the last few days, two of our four toilets have declined to flush properly. So, I have had the job of taking them apart, replacing the siphon mechanism and the ball valve in each. These have been long and tedious jobs, and the worst part of it is, that at the end everything looks just as it did before. The toilets flush nicely now, there don't seem to be any leaks, but there is no visible result of all my hard work.