I've tried geofencing a couple times. Never worked very well for me. I found it to be unreliable, imprecise and delayed by a few minutes. It might work for something like: remember to buy flowers for my wife when I leave the office, but I tried to set it to remind me to get my reusable shopping bags out of the trunk of the car when I arrive at the grocery store - it reminded me about five minutes later when I was already in the store. Other times it never reminded me at all.