Speaking of 'use it or lose it' the hippocampus of the human brain shrinks a we age, but less rapidly if we exercise it.

This involves not using Google Maps or any other GPS to find your way around, except when you really need it, for somewhere you've never been to before, but remember to rely on memory to find your way back.

For proof of this claim go ahead and research the hippocampi of the drivers who work for the London Black Cab company and "The Knowledge," a test they must pass in order to qualify for working as a driver in this company.