Like many of you I use my GPS mostly for marking where I park my truck. Also for marking rubs, scrapes, water, etc. If I'm not actually using it I turn it off to conserve batteries. I've noticed that somtimes in a little tree cover it will lose signal anyway.
Always carry extra, fresh batteries
Always carry topo maps of the area you are in, or forest svc. maps minimum
Always carry a compass
Know how to use the GPS BEFORE going out in the woods!!
Several years ago my dad, my brother in law and I had an elk hunt. My dad bought my brother in law and I new GPS's, the unit wasn't the cheapest but by no means was it top of the line either. We decided to learn how to use them on the fly...bad idea. This particular model seemed to work fine; set truck location, head into the woods. Unknown to me, if you weren't traveling consistently at a fast enough pace, the unit would not track/update your position. The pace you had to go for it to function was just a little faster than you can trek up hills, over fallen trees etc. When I would get on flat ground again it would update and tell me I'm such and such distance and what direction to go. When you know you've gone past where you should have found the truck and the unit updates again telling you to go a different direction with more distance it starts to become a problem. I relied on a piece of equipment I was unfamilliar with, and with no map or compass, and not paying enough attention because "I have a GPS" and ended up lost. I was only 3 hours late for our rendezvous at the truck not to mention worn out.
Know how to use the GPS BEFORE going out in the woods!!
I have a better unit now and I know how to use it. It's a Garmin GPS12. It's simple, it works well, I can upload/ download waypoints to and from my topo software.
az-jim