Bought a Garmin Edge 510 and a GSC 10 cadence sensor to replace my self-disassembling, decrepit Edge 300. I'm loathe to replace anything that works, but the 300 had a periodically iffy battery the last three years. Sometimes it would just random shut off during a ride, then when I was about to replace it it would be fine for six months! Now the battery doesn't last a ride, the case is splitting, the face is all scratched up, and the buttons are glitchy. Yeah, replacement time.