I did carry a sat phone on one of my first solo trips.  I guess it proved useful because I was informed of a family emergency during my trip.  Unfortunate, being 3 days from my exit point and 2 days driving home meant that I couldn't respond to the emergency personally, but was able to "contribute" otherwise. 

Despite this 1 in 1000 chance of really needing a sat phone, I decided thereafter not to take it, but rather a SPOT instead.  Since much of my travel involves paddling solo (sometimes with other paddlers, sometimes all alone; sometimes in familiar waters, sometimes virgin waters for me), there is a good chance I'll have to effect a self-rescue if it should ever come to that.  There is a descent chance, even when traveling with others, I could be alone (and 2-way radios I've found to be a waste of weight to carry). 

But all that aside, my wife and family care about my well being and especially my dear wife does worry when I'm in the bush (whether plying northern waters or on a mountain top some where).  So, the most significant reason I take a SPOT is for their piece of mind. 

My routine is much like some of those already expressed.  When dinner time rolls around, I'll take the SPOT to the edge of the campsite and engage the "OK" button, check to make sure that the unit has engaged satellites (usually takes 3 for a lat/long reference), and walk away.  I return after dinner is completed to retrieve the unit and pack it away for the next day.

What is not so nice is on that cold, windy, rainy night when you are already tucked warmly into your tent only to remember that you forgot to sent the nightly signal.  NOW, THAT SUCKS!

dd