Insurance
Totally apart from the issue of its usefulness as an instrument for hobbying, a cellphone is an insurance policy, possibly on your life. What if your car breaks down in the middle of nowhere and it is -60 degrees outside, or what if you get stranded somewhere in the wilderness and nobody knows where you are? What if you are attacked by a bear while on a fishing trip, and fend him off, but sustain wounds that are bleeding heavily? Do you need a cellphone then?
In late 2006, a mountain climber got stranded on Mount Hood in Oregon with his friends, due to a sudden storm. Two of the friends tried to make a run for it to get help, while the mountain climber, who had a cellphone, built a snow cave and then called 911. After 911, he called his children and told them he loved them. Those were his last words. His frozen body was found exactly one week later. Rescuers could not get to him due to avalanches and storm conditions, however, his location was known due to the cellphone and he otherwise would have been saved. At least his body was recovered. The bodies of his two friends were never found. They presumably froze to death, and their bodies will be discovered perhaps many years from now when there is a signficant melt from global warming and someone sees a leg popping out of the snow.
There are numerous stories of lives having been saved in these situations. For these reasons, I always carry a cellphone with me when I travel, even though I do not use it on the road.
One other thing- last year at the Jazz Festival I used a cellphone to determine the location of a friend right before the Stevie Wonder concert. There was no other way I would have been able to find him among the mass of 200,000 bodies that were crammed into the area within several blocks of the main stage. How else would I have found him?
In terms of application to the hobby: PMikey, you can shut a cellphone off and claim the battery was dead, if there are calls you do not want to take. But, a cellphone enables you to know if an appointment is cancelled suddenly. I have seen a few providers who have texted me to say they would be late, or had to cancel. It's better than waiting like a dumbkopf for someone who is not showing up. I really hate wasting time and to me a cellphone enables me to avoid wasting time.