As a tool, it's a life saver. After time, it's an annoyance that the driver no longer needs or uses. 3, 5 days. 3 weeks if necessary. Who cares?
Yesterday I go up to a dock blocked by 2 Ground drivers. First off, they don't even need the effing dock because they have 5 packages. The first, who has been there 2 weeks, is training the second, who is on his first day. Between the 2 of them there is enough brain power to run a flashlight. After I roust them off the dock, they park directly in front of it looking at the GPS to figure out where the Hell they're going next. This is not making me, UPS, or Roadway very happy.
What you hire needs GPS, and that's because they're freaking morons.