buying a GPS is like buying an insurance against getting lost

It may be helpful only occasionally, such as road closure, missing a turn, getting around in a city, ...

Most importantly, with a GPS, there is no worry of getting lost. Now you can deliberally get lost :-)

But I have to tell you that it probably bothers you more times than helping you. To avoid that, it definitely better to read the maps ahead, then use the GPS but not completely follow it. Sometimes, the GPS has to be resetted (it will get lost it you drive round and round a few times).