[Stuart]

I wear a Casio G-Shock radio controlled watch. Because it's radio controlled (ie checks the time/date automatically with the signal in cumbria) and light on electricity, I don't have to worry too much about whether it's accurate or not (indeed, I can't remember the last time I had to set it).

My iPhone does tell the time accurately, but that's assuming it's got battery power, and assuming I'm in an area safe enough to be be flashing a smartphone worth several hundred pounds in. Neither is a given if I've been out for a drink.