More Words, Deeper Hole

String mops. They hold up better and, as people said above, they're washable. To use, simply draw the mop towards you, pulling it in a figure-eight pattern at the same time so as to cover a wider swath of floor. (Most of the people I trained on how to use the string mop assumed the proper mopping technique was to aimlessly push it back and forth, with is sub-optimal.)

I also find string mops more effective than sponge mops. The only drawback is that they work better with a bucket with a water-squeezing attachment, which probably costs more than the mop.