John Armstrong said:
...And like PC's with their upgrades they become slower and slower due to the extra processing power required for the new programmes...
Well... I don't really think that analogy transfers over from computers to GPSRs, because the 'program' remains more or less the same for the life of the GPSR. The only thing that could change is the cartographic data, and additions to the cartographic data will not slow down the calculation of a route unless new roads have been added
in the area you are routing through. In other words, if the next update of CN Europe adds coverage of Eastern Europe, or some new housing tract near Glasgow, but you are calculating a route from one side of downtown London to the other side, GPSR performance won't suffer at all, unless someone has added new streets to downtown London.
So far as POI's go, sure, if more POI's are added, then it will take fractionally longer to look up all the POI's of a certain type within an area. But, that is not an everyday activity.
What really causes people to buy new GPSRs is this: They are generally quite happy with what they have, until they see something newer that either has a bigger or better display, or accomplishes the job a heck of a lot faster, or brings in a new trick (e.g. GATSO proximity alerts). At that moment, they then decide their old unit is no longer satisfactory.
Michael