All current Garmin automotive devices include lifetime maps for the region in which they are sold. You cannot transfer an old lifetime map to another GPS. Yor waypoints (aka favorites) can easily be transferred. New Garmin devices no longer use "routes" however, they have something new called "trips". I think they will be converted when transferred, but not sure. Worst case, you can transfer them to Basecamp, then send them to the new GPS where they should automatically be converted.
Free third party maps (such as most of the maps here) can also be easily transferred. Commerical maps that were purchased from Garmin or other companies might be locked to the old GPS and not work on the new unit. It really depends on the specifi map.
This is really the wrong site to ask these questions however, the forums here are primarily for discussion of the free maps available here. I'd suggest starting a thread here for any other questions related to Garmin automotive devices and products.
http://forums.gpsreview.net/categories/garmin-auto-forum-garmin-nuvi-forum[edit]I see that you have actually purchased a used Nuvi. Theoretically, you will still be able to use lifetime maps on the unit IF it previously had them. You would not be able to transfer your own lifetime maps to it however.