When you buy a SatNav you may (or may not) get continued support in the form of updates to the mapping software. Typically you are told you will continue to receive these updates for the life of the product. You may feel that this means for as long as the product remains usable. And of course this perfectly fair day-to-day meaning is not what the supplier means - he means that support will go on for precisely the length of time that he wishes to provide it and not a second later. And there is nothing you can do about it.
For a wonderful example of circular reasoning, here is the full explanation from TomTom's website about what they mean by "lifetime" of a commercial product:
"lifetime" means the "useful life" of a device: "ie: the period of time TomTom supports your device with updates, services, content or accessories. A device will have reached the end of its life when none of these are available any more."
So the lifetime is as long as they do updates and as soon as they cease then, miraculously, just at that moment, the lifetime of the product expires. The one defines the other. Or to put it another way:
Q: How long will you provide updates?
A: For the life of the product
Q: When does the life terminate?
A: When we stop providing updates
Q: And when will that be?
A: When the lifetime of the product expires etc etc
I own a SatNav, not made by TomTom, and which did not come with any warranty about updates. I don't care. It's still accurate for all main roads and it's probably cheaper to replace it in a year or so than to buy a more expensive model that does have the "guarantee" which will then be deemed obsolete by the supplier a few months later. What I will not do is buy one that does have a "guarantee" unless they tell me how long that is going to be. In years and months, not whenever someone in their Tech Dept flips a coin and pulls the plug.