Both of mine weren't too bad on batteries, but neither one lasted more than 6-7 months, before becoming completely useless. Haven't gotten around to sending it back in, and getting #3. Been kind of interesting in the new White's, just need to find a dealer that doesn't use PayPal.
I used a rechargeable 9.6 volt battery in the first one, lasted a month or so, before needing a charge. When it started falsing, I went back to alkaline. The second one started falsing about 2 months after I got it. Not to bad at first, just occasionally, not every hunt. Put a fresh battery in when it was falsing 2-3 times per hunt, but it continued getting worse. 6 months, pretty much every hole, and had to cycle the power several times. Garrett customer service is great, just not thrill I had the same problem, with the replacement they sent.
Think it's luck and persistence. You either get a good one, or you keep sending them in, until another satisfied customer story.