I've never had a GPS that outlasted the usefullness of it's maps. The display dies, the battery dies, etc. I don't think maps need updating every three months, I've never had the need for maps updated that frequently. I've never been someplace where it really matters, and I'm certainly not going to turn the wrong way down a one way street because the GPS said to do so.

Garmin for example in their lifetime maps state

This map update only can be used to update the preloaded maps that came installed on your Garmin device.¹ For example, a device preloaded with North America maps cannot be updated with nüMaps Lifetime Europe, and vice versa.