I think we all seem to have different ideas of what priming is.
If you have to run Google Maps, GPS Gate, Astrolauncher, Live Search, etc...then you are priming your GPS. Certain Apps run without priming (Garmin XT, Copilot Live, Sprint Nav, and a few others).
But, in order to run Tom Tom, Inav, etc, you must prime your GPS first, meaning another app will open the GPS port.
The good news is that with a lot of the priming apps, you can make it so that the whole priming process is transparent. This means that you run the priming app and the GPS app simultaneously and the GPS app will seamlessly pick up your current location with no other user interaction.
This is a common way to use Astrolauncher (priming app) with TomTom (GPS app)
I use this method myself and it works flawlessly.
-s