It's going to depend on my schedule. I'm lucky in that some days I have a whole day to play with. At other times, it's pretty hard to squeeze in a session, let alone more than one. Right now I'm doing physical therapy for a torn rotator cuff (never knew I had one--sounds like something that should be in a car) three times a week. Although it only lasts an hour, it's almost an hour each way to the clinic. Poof, almost half a day, gone. (But at least I won't be needing surgery, that's the main thing.)
I do up to three paras a day when I have those "free" days. I work them in between other things--work on something awhile, take a para-break, then back to work, etc. On days when everything's coming at me quickly, maybe one.