But I try to book same day or next day and very rarely more than 2-3 days out.

Too far out, I've found that some providers in general are not as organized or as professional as the people I deal with in the business world.

Too far in advance, but there is such thing as not booking in advance soon enough.

Typical consulting answer...

"It depends."

As OTB said, everyone's situation is different. So do what's best for you.  My personal preference is to usually book 2-3 weeks in advance because my schedule has few openings, so I want to be sure I can get on the provider's calendar during one of those rare openings. I've found the top-notch Minnesota ladies are typically very professional at managing their calendars and don't mind booking out aways.  But I realize also some providers may not like taking appointments so far in advance, so if you want to do that be sure they're ok with it.  Then reconfirm during the wait time, if the provider doesn't do it first.

I like to book a week or more in advance, because I have limited openings. This tends to work better with ladies who have regular incalls.

... on when she takes bookings (some require 24-48hrs notice for incall etc).

I always prefer to book 3 to 7 days in advance. The providers I see usually prefer this. I also know my window of opportunity and advance booking assures me my preferred time.  This also avoids the last minute hassles.  I enjoy the anticipation.

It depends a lot on when I would like to see someone and what their schedule is like.