I think it really depends on the lady, and if she is required to stay at the incall, or if she only comes in once a liaison is booked. If it is her own place, then there are always the regular day to day things that need to be done (in between jumping on the bed an having lingerie pillow fights with her other gorgeous girlfriends of course ;-)
From a work related perspective, there is always writing more ads, posting, emails, screening, updating your website, answering emails, returning calls etc. Working out, picking up items needed for liaisons, from typical supplies to champagne, chocolate and anther enhancements for the next sexy encounter.
On a more personal level, a lady can go to the gym, get fresh air, grab a bite with a friend nearby, work on personal hobbies or other jobs, trade stocks, study and write papers, or do pretty much anything else that people do in their spare time. Smart phones make it pretty easy to continue life as usual and finish all the less sexy things that all of us need to do each day.