Do you ever hear your toilet refilling for no apparent reason? You probably have a leaky flapper. If you use those drop-in chlorine tablets in your toilet, I can pretty much guarantee you have a leaky flapper. Those tablets deform the flappers and make them leak.
Thankfully, replacing the flapper in your toilet is a very quick and easy DIY project. Most of the time. Of course, there are always a few toilets with old or unusual guts, and those might not be so quick and easy. For the rest of the toilets out there, I made a short little video showing how to replace your flapper. Check it out:
After I recorded this, I realized that I kind of skipped over the chain adjustment. I consider this part to be pretty much common sense; the chain length is easily adjustable. The chain should be long enough to have a little bit of slack so you don't need to jiggle the handle to get the flap to close, but short enough to get the flapper to lift when the toilet is flushed.
Oh, and of course, you'll need to turn the water back on when you're done.