Hi,
That's a very good question.
For best practice and depending on your time zone it would be professional that it is done within convenient business hours. Therefore both Experts and clients would come to a time that is convenient and professional. We are here to help the client so if you give a timeframe and it is not convenient for the expert for whatever reason, a suggested suitable time would be made.

We are here to help you out with your problems. So everything would be done according to you. Client can schedule there timings and if the timings doesn't match, we can proceed the procedure for the next day as per clients requirement.