Depending on what she needs to trim and how much, I second the rechargeable trimmer instead of a plug in version. I used an 18v Black and Decker version for 3-4 years on a 1/2 acre fenced lot with ~500' of wood fence and 20 - 5' tree circles to trim around, plus sidewalk, driveway, house. Doing the fence & tree circles used 1 battery, the driveway and everything else used the 2nd battery with plenty to spare to do other things if I wanted. If you weren't handy it had prefilled spools you could buy and drop in as needed although 1 spool lasted me a MN summer using it every week. You can also just rewind the spools with bulk string. If I just needed to trim grass on a normal city lot I'd definitely get one again vs a gas or plug in version. Especially since that was 3 years ago, the ones I've seen now have even better batteries and longer run times. We moved to the woods so now I use a brush trimmer instead otherwise I'd still be using the little battery one.