@Hans-Kremers said:
It sounds to me that people who want to avoid their navigation device recalculating the route they planned are actually looking for turn-by-turn navigation on a track rather than on a route.
Unfortunately, very few navigation devices support this. Most devices that offer track-based turn-by-turn navigation are designed for running or hiking and rely on dedicated file formats that contain both the track and the navigation instructions.
For motorcycle navigation, the only solutions I know that provide true turn-by-turn navigation on a plain GPX track are DMD2 and OsmAnd. Of the two, DMD2 is much more intuitive and easier to use, whereas OsmAnd offers similar functionality but comes with a significantly steeper learning curve.
In the Garmin XTs, you have multiple options for handling off-route scenarios. You can do a traditional auto recalculate, automatically disable off-route recalculation, or select 'prompted" to have the choice of which option to do. In settings, I personally chose the "prompted" option. So when I go off-route, I'm given the choice to either recalculate, or do nothing. The "do nothing" tells the Garmin to pause the route until I return to the route-line, much like following a Track.
The prompted disable gives me optimum flexibility. If I'm intentionally going off-route for a short distance for fuel, food or whatever, I know how to get back. I don't want to take the chance of a route recalculate unless it's absolutely necessary. Something else can possibly change that I don't want changed. The strategy works very well.
So, to your point, the Garmin XT's provide true turn-by-turn Route navigation with Track like flexibility for off-route scenarios. It's one of the main reasons I stick with it.