I been using spot for the past 5 yrs, initially with spot 1 and now with spot 2. For one year I did pay for tracking option which I found is battery draining and you need to carry extra set even for a 1 week trek. So I discontinued tracking option.
As Steve pointed out you need to keep it on at least 30 mins to make sure the signal reaches satellite. The way I do this is, at fixed times in the day, one at 9a and one at the end of the day I send the signals. It will send the coords of the place where you pressed it first, even if you are on the move. So I hang the device on my pack (south facing) and continue walking and switch it off at my next hourly stop. This worked very well during my recent HST trip.
Again in the deep valleys like Kern river trench, though the device shows it did send the msg., it was not received by the family. So be aware of that issue and let the family know your intended plan before the trip.
