Even if you clearly state on your profile your working times they would still go "when you working" so I never bother with a time frame or with slots that I have available as they would either go "that's too late", "actually I wanted next week", "that's too early" or the famous "I will let you know" leading to nothing. I'am making them tell me when they want to come and if they keep repeating the same question without answering I block them