I don't believe the Fluidmaster kit is the sole culprit here.

In certain environments, the chlorine level in the water is quite high and the rubber degrades at a much faster rate than normal. One house in VA that I'm quite familiar with will need attention to the toilets every two years.

However, in NY, the chlorine is reduced and the rubber will last 5-10 years or so. In general, I've been pleased with the Fluidmaster kits. The flappers are typically the first thing to go.