Review on Lignomat Mini-Ligno E/D Moisture Meter by Tim Harrington

The 9V battery is completely empty. Sure, it's zinc charcoal batter (they're less likely to leak once they're on the shelf). But I'm wondering how old this thing is and will it last as long as a newer one? I tested it with a neighbor and it gives the same reading as his, so that's good. I believe he lived with him for several years and it is surprising that his original battery was weak but not dead. So is the one I just bought older than him? My battery is completely empty, his battery is low.