I use the map functions when I'm going somewhere(like home, when I get lost) - I've gotten lazy in the car and also like it on my bikes. It's come in handy a few times - namely where the 705 saved me 5 miles with a short cut in the rain a couple weeks ago. For the most part, I could have used a "regular" computer with Cadence/HRM, but you don't really save that much. Tracking performance and ride history is also nice for training - with the GPS, you can compare the same routes or stretches of road and see improvements over time. It's also nice to see where you've been. "Need" might be a stretch, "want" certainly works.