For many years I wore a sports watch compete with GPS and Heart Rate Monitor
It was a trick to set it up each morning, make sure connections are made, that the batteries are strong. Sometimes it just didn’t work.
It did provide some nice historic data, but I found it distracting to watch my heart beat, I use a high heartrate as an excuse
I tried to use the watch at a marathon for splits, didn’t practice enough with it, and it was a disappointment.
Ideally you could receive some positive feedback on your fitness. Maybe I’m not “there” yet
I didn’t replace the battery this last year, and relied on my iPod instead.
Gypsy Marathon 