I have a DM42 and have had it a few years. I haven’t had to replace the battery yet. There are times when I used it everyday, and times I leave it sitting on th

I have a DM42 and have had it a few years. I haven’t had to replace the battery yet. There are times when I used it everyday, and times I leave it sitting on the shelf for months. I also have an HP42, and it eats batteries. I assume it has a fault.