Is using a gps all the time in your car a good thing to do?

Depends: On what you think a "good thing" is. There is no evidence that it is harmful to your health to use gps. My own feeling is that if you always have a computer telling you where to go then you are not using your brain and not gaining a sense of the local geography. This is potentially hazardous when your gps fails and you are in a bad area and never learned your own way around town.