Swim Training Time...

I record the elapsed time starting with my first set and ending when I touch the wall on my last set. I use my watch to record individual sets. I record these in the comment sections for endurance and speed intervals. I recently stopped recording times for drills, just record what and how many I did. When I feel really OCD I record the lengths of my rest intervals, but that is rare. If something interrupts the workout, needing to get out for somereason, chatting with a pretty girl or what ever, I stop the watch and restart when the interruption ends

It makes sense to me to log the time of the whole workout. As Av8rTx said.

In my mind, the rest intervals are part of the workout. If I have a significant interuption (like when I swim with my daughter), I try to estimate it and subtract it from the elapsed time before I log it.

I suppose it might be interesting to know how much time I spent actually swimming (and it would make the calculated time per 100 yrds better reflect how fast I swim), but I can't imagine how I would keep track of it.

If I'm doing "4 x 250 with :30 rest" I could just subtract the 2 minutes of rest. But what if I'm doing "10 x 100 on 2:00"?

While the rests may be part of the workout, I DO want to know how fast I'm actually swimming.

It's not at all hard if you have a watch that does laps/splits: hit the split when you hit the wall, hit it again when you push off for the next interval.