1. You indicated that you've used your Edge for a few years -- have you updated your maps? I mean, Garmin's routing is far from perfect but not that bad. (btw, maps and routing tables are two different beasts).

2. You may not want to give up -- routing and turn-by-turn (tbt) navigation can be a godsend. But there are a couple of things to keep in mind:

• There are many routers, and routing options. Try a few. Google maps is very useful to explore a route on your computer. But until you learn how to move a route to your Edge, it may not be the best option. Garmin Connect provides a simple/decent interface and will sync it to your Edge. Personally, I like to explore on gMaps and finalize with Locus Pro/Android (making it possible to generate new routes offline and send them to your device. Invaluable). Wrt options, try car/bike/foot and see how they differ. Some routers impose strict rules that may add lots of miles to avoid a highway that you'd be perfectly capable of riding.
• Routing softwares are far from perfect. They sometimes think there's a road whereas it's been closed or is impossible to ride, or will think that a footpath with stairs is fun to ride with a loaded bike. It is a good idea to check, although eyeballing a route is no guarantee that your route will be the best.
• TBT navigation on Garmin Edge (I've used the Touring model) was a nightmare. Be sure to check off the "update route" option (or whatever the name is now). Otherwise your carefully planned route may be replaced by something that will not make any sense, the moment you stray from your initial plan.
• If/when you ride off a planned route, your Edge can no longer suggest a direction (although, it may depend on the model. Some do not have maps+routing tables and will become useless if you drift away). Normally, if/when you return on a planned segment though, tbt nav should resume.

3. You may want to use your Edge on familiar terrain, maybe in your car, until you become more familiar with it. Start with (very) short routes (home -> shopping mall -> home) and add complexity as you master a "routing level" (more complex would be a longish route where you'll take an unplanned side trip, say, for lunch. What happens if you turn your Edge off/on. Can you resume your nav?). After a while you'll give nav seminars at your LBS