Marshy
I have used a handheld GPS for many different things for about 10yrs now. I have my old B&W Garmin Etrex Legend, but my recent GPX5000 detector purchase came with a Garmin E20 colour.
The primary reason for GPS use in the goldfields is not to record finds, but SAFETY. In the bush and wandering around, head down and then digging for a couple of hours, it's very easy to lose your sense of direction. The scrub is thick enough to lose view of your car in less than 50 metres.
The first thing I do is mark a waypoint when I stop and rename it car. I then turn it off to conserve battery. If I lose my direction to the car, I switch it on do a GOTO the waypoint and follow the GPS trail.
The second thing I do with a GPS is not actually handheld, it's on a windscreen tablet with GPS, Oziexplorer and VICMAP. I use this to navigate tracks, it also logs where I go and I can mark waypoints at spots I want to come back to.
BTW, I'm also W suburbs. Happy to meet up if you want further advice.