If I am looking to make an appointment with a provider, how long should I wait to call back if I can't get a hold of her on the first time. Usually it wouldn't be a problem, I just have a very limited availability.

If you didn't leave a message, then call back in an hour. If you did leave a message, then wait a few hours. After that, assume she is busy, doesn't have interest, or is not working right now (out with friends), etc.. Go on to the next lady on your list.

don't hear back within a day or so, move on to the next provider on your list.

I always require that a gentlemen leave a message with a name, callback number & time frame that I can call him back... if all that is not in the message, they will not get a return call. And please, don't call a provider every hours, 4-5 hours in a row... if she hasn't called back/answered by then, she probably has prior engagements. There have been many instances where I have 3-5 missed calls after a 2-hr appointment, but not one person has left all  the needed info... or the guy that called 7 times in 1 hour(those NEVER get call backs, and if this behavior continues, they go on a do not see list).

Also, if she has a calendar on her website, make sure she's even available during the day and hours you're trying to call. I get plenty of calls after midnight, even though I don't work past 12, and those guys never get callbacks the next morning, unless the left detailed call back instructions.