Just here troubling deaf heaven with my bootless cries...
I'll just continue to sit here reading you guys, jealous that you've got enough time to consider one long or two not-as-long workouts a day.
I'm living vicariously through you for sure, Chris.
SO it's an old thread, but I'll jump in as I just had this conversation with my coach this week.
2 a days are helpful in two situations. Maybe more.
First one: you are new, recovering, or working on a specific stroke problem. It is better to do shorter sessions where you can focus and do good work than a long session where you get really tired at the end, and your technique etc fall apart.
Second situation: you are very fit and have the time to put in two excellent sessions.
I'm right now trying to correct an issue with my catch, and I am coming back from back injury, so I'm in the first one. Two a days can be a super effective tool to build base and endurance, but that said, once a week I still do one long swim....