When using a GPS always carry a compass with you.When marking a spot on your gps make sure you have a good lock on your satellites before you mark your spots. One time I drove my truck about 3/4 mile in the woods on a logging road, I got out and turned my gps on to mark the spot of my truck. That day I was having problems with locking on to the satellites, the gps would aquire position and then loose it. It kept doing that, so when it locked on I marked the spot and then shut the gps off. After walking around in the woods for a couple of hours I decided to go back to my truck. I turned on the gps and when it locked in I started going back to my truck. I got to my destination and there was no truck no logging road. So I took out the compass and headed west because I knew the main road was that way. I made it to the main road and then found the logging road I drove in on and found my truck. When I got to my truck I turned on my gps and it showed my position almost 1/4 mile from the spot I marked in the same place before. A gps is a wonderful tool but make sure you have a good lock on satellites before you mark a spot, and always bring a compass along when you venture in the woods.

There is something I have never had a problem with.
So far my GPS has always bought me back within feet.
I set it North up so I have to use a compass with it. I also take a reading with the compass as to the direction of return based on that GPS direction. And of course prior to entering I determine the direction of the road I am leaving from. If no road I sill do a lot of it the old way. Note book, compass, bearing, and steps to the next marker point.
The only time I have ever been lost in the woods is the time I thought I was lost. I just stopped, regained compositor, waited for daylight, checked old faithful (sun) and headed back to camp.

The only time I got lost was trying to use my gps to get into or out of a spot.

Never had that problem with my GPS. The only problem I have had is NOT being able to get a strong enough signal to navigate my way back. Of course I do have a cheap GPS.

Bottom line is NEVER rely on your GPS to get you out of the woods. Like John says,

Mike, that was the firstime that ever happened to me with a gps. After it was over I kinda laughed and wondered what the heck was going on. But I knew even when it showed position aquired I should of gave it more time to get the track of more satelites.I'm not trying to turn anyone off from using a gps because it is a great tool. I have topo mapping on mine and let me tell ya, it shows you everything. You can see main roads, logging roads,creeks,ridges,swamps,lakes, ect.Its a great tool to use mushroom hunting,I wouldnt be without it.

I remember the first year we used a GPS, and it was a little confusing at first (just because we are a little slow ), but now I wouldn't even think of going without it...

I am concerned about weather affecting a signal when I am in the middle of the woods.

I concur, when heading into the woods make the first mark the car, take extra batteries, a map and take a compass. Since I have been lost twice and did not really like it both times and do not intend to get lost again. I take some additional precautions. The GPS has a hole in the case for a lanyard, use it. As I teach my Boy Scouts “If you don’t want to lose it tie it to yourself” The second thing I have done is to add Velcro to the back of the GPS and to my hunting jackets. That way the GPS can stay out of the pocket and upright improving the chances of staying locked on signals.

I use a garmin and can't seem to get a signal in the woods under the trees should i leave it on at all times. i get a marker and shut it off to preserve batteries is this wrong.

I too have had gps fail to acquire a signal from time to time. This is most likely to happen in areas of high elevation changes.