I'm starting a twice a day experiment right now. I'm not adding any volume, just splitting it in half. Heavy 6-8 range compounds in the morning, then 8-12 rep isolation work in the evening. I think it's important to resist the temptation to turn it into two FULL sessions every day.
Now, it helps that I have two gym memberships, and one of them is located a one minute walk from my apartment. If getting to and from the gym was a hassle at all, I wouldn't do it. Also I'm currently working in my apartment, so I'm not really using a lot of extra time here. I figure why not give this a go and see if my gains improve, seeing as the conditions are favorable.
x2 on the soft tissue work and workout nutrition. And stretching.