Swim Workouts - Minutes vs. Yardage

I asked the same question to the coaches 2 months ago when I started my plan.  Here's the answer they provided:

"The time for the swims is going to vary b/c the plan is created for such a wide variety of swimmers - fast/faster/fastest - (no one is slow!) - so if you have the time and energy, you are always welcome to do more as long as you aren't getting injured or overdoing it where you are compromising your next workout. "

I use the training program as a general guide to follow, not a bible that has to be followed.  For swimming, I have clear personal yardage goals, not total minute goals, when I start a workout.  I expect that this yardage will translate somewhat near the minutes that my plan suggests I should be swimming.  If I have a good workout, I don't worry at all if I'm over or under on the minutes.  FWIW, I usually seem to be under...

Ahhhh..."fast/faster/fastest" hahahahaha!  Even under that idea, I'm still "slow". 

I swim for time.  There's no way I can do the workouts listed in my training plan anywhere near the time guideline.  So, I modify the workout a bit to keep to the general idea (whether it's a long, steady workout, or sprints, etc.).

I figure that my workout doesn't give me mileage runs or rides, but just times (run for an hour, bike for 2+ hours), so that's what I do for those workouts.

But that's just me.  If I had tried to do last night's swim workout in its entirety, I probably would have been in the pool for nearly 2x 45 minutes.  Plus, anything after about 1500 yards is a waste, since I'm tired and my form starts to suck. 

I was thinking about this post, in relation to the fact that many of us swim for distance, and bike/run for time.  But why?  Doesn't the same hold true for running and biking... that the actual distance will vary?

I swim for distance and bike/run for time, but now, I have no idea why.  Now, it doesn't seem to make any sense, differentiating between swim and bike/run. 

I swim distances that fit in during my lunch-hour swims (3x's/wk).  So, usually that's 45 min (50 min tops) of "pool time".  For me, that works out to 2000-2500m depending on the type of swim workout.

So, I guess you'd put me in the "Minutes" category, technically. 

Not maxing out my available "pool time" (equivalent to swimming shorter distances) feels wasteful to me for some reason.

I plan all three for time, but I'm picky about logging my progress, so I plan a goal distance as well. Especially when running and biking, I pick a measured route that I will finish in about the right time.

 In the pool I simply aim for as many laps as I can in a given time, of course completing my last lap. I measure my progress by my pace.