First time seasonal.. question on tanks and slide?

this is my second season with a camper and the 1st at a seasonal site(tired of towing after one season). We will be weekenders at our seasonal site. im just wondering if others always flush and clean the black tank sunday before they leave or if I can leave it be until it starts to get full(2 weekends or so).
Also, what about the slide. is it ok to close it on sunday and just open it again on Friday night when we come up? I do have a slide topper.. opening and closing once per week shouldn't wear out the slide or motor will it? and I guess I should ask the same about the awning? I notice a lot of seasonal campers keep there awning open and leave things under it, I don't know if I like this idea, rather just close it... thanks...