I used my e-trex legend while traveling.......Lay out my routes and download to the GPS before getting on the air plane......when I got the the rental car I'd boot it up, put my laptop in the seat, and GO TO........
Because of the way I use the device while traveling, I constantly download and upload, Mapsets, routes, and waypoints........It keeps the "clutter" down.......
I keep everything.......so when I get ready to go hunting......I upload the info I need back to the device.......