This kind of depends upon who you ask.

Here.... it would ***never*** be an option. 

Much the same way I do not work with a client standing behind me "dictating changes". There is no *feasible reason* why a client needs to be that close. If they wish to micro-manage to that degree, they need to hire an employee. As a freelancer, it is asking far too much in my opinion.

In addition screen sharing, basically gives the client insight into *how* I work or what tools I use, and if I'm not careful, personal items I do not want on display to clients.

No. I would not permit **any** screen sharing at all from my system. 

If more immediate changes are necessary due to a looming deadline or something, then a *phone call* and revisions while on (speaker) phone *may* be permitted on **very rare** occasions. With email used to send revisions. This provides a "wall" between what I do and what the client sees while still providing instantaneous feedback if warranted.

In short... I am not a "while you wait" or "on demand" service. 

Would a chef allow a restaurant patron to come into the kitchen and dictate how much of what spice was put into which dish at what time? OF course not. The chef merely needs to be told "no cilantro". --- They may as well ask to sit on my lap while I work if they want to screen share. To me, it is just as ridiculous of a request.

But, again, that's merely *my opinion*. I'm sure there are others that have no problem with it.