Annually drain and flush your water heater. I didn't know about this, but a neighbor brought a hose over (it's a condo building so not many hoses around) and we took advantage of it to clean the balcony. It wasn't exceptionally filthy, but we noticed a marked improvement in the efficiency of the heater as well as much less sediment in our showers/sinks. Also, when they get back in stock, get a leak frog for yourself and everyone you love. I forget exactly but it was about 10-15$ and it works incredibly well as an early warning for water problems.