For 4-6 weeks before a 1/2 IM, every Fri. I will swim 1x2500 In a crappy, overheated 3 lane 25 yd pool in precisely 40:00. My last 1/2 IM in a relatively calm lake was around 32:00.

With my bike and run times, it just doesn't make sense for me to put in the extremely hard work it would take to get into the 28:00 range. It would require a consistent 2-3 hours more in the pool every week and I can gain more time from improving my cycling and running.