I think they make a little thing that can hang down in the water to count laps. I seem to always lose track of how many laps I've swum, so I just wear my watch and start the chronograph when I start swimming a longer set. I know I swim an average of 50 yards/min so I periodically check it to see where I am at. It works well, and it's interesting to see that some days when I feel fast, I'm still slow, or when I fell crappy, I'm actually not as slow as I thought.
This weekend I swam a mile straight for the first time ever. I was really pumped!! Poor Red heard about it all weekend, LOL. I try to get an average of 2000 yards per session, but that's including warmups, drills, various sets and a cool down. My goal was 20 laps straight, but I was feeling really good at that point and decided to try for 25, then 30, then 35.
Woot!!
Monster, when I was in college, the University Wellness center ran a program that you kept track of how many yards you swam, and the goal was to swim to Cuba during the semester. My workout buddy and I made the 90 miles, and earned a T-shirt. It was incredibly motivating, especially because we swam in the mornings, usually when the swim team was practicing. Those guys could kick faster than I could swim at that time. Seriously.