I have motion detectors that screw into the light socket in my garage.  For whatever reason our 2 car garage has 4 separate light switches.  Motion lights have made it much nicer and I'm not leaving them on. Some work well. Some don't.  Some last forever.  Some fail quickly. I can't find a rhyme or reason.  But it's nice to walk in and the lights come on.  

These light switch guards help keep from them being turned off


Here's a couple of the motion detectors I've used.  Photo just as an example, not a recommendation