I have been wondering about this too.
My babe is 6 weeks this week- right now I go at night after DH gets home and after I feed the baby for bed, usually around 8:30 or 9 pm. However, I am getting sooo antsy and bored in my house, I would love to go in the afternoon. Right now I feel guilty taking him and leaving him in the day care. I worry about him, I guess and I feel like he should be spending the time at home.
I suppose I could go during his nap time, so I know he would be sleeping, but then I feel like he should spend his nap time sleeping in his bed rather than in a car seat....