I run auctions and will try to have some finishing every night. As a non store I only get 40 freebies a month, so will spread that out of the entire month. Of course if there is a free listing promotion I will use those as well, but if there's not, I know that spreading the 40 out will ensure I have listings all month (I run for 7 days).

I've had buyers bid on different things that finish days apart. I send them a message after they get the first one asking them not to pay until they've finished buying so everything can be sent together. If they have bid on items finishing later than their first one, I'll sometimes end them early if they are ones that have been relisting for a looooong time. I have about 15 items that have been relisting for 2 years and a buyer has bid on several of them, with the first one finishing tomorrow and the rest by the end of the week. I'll surprise them and end the others early so they can get them sooner and not have to wait.

If your items are buy it now's, most buyers will check your other items and buy whatever else they want. If your items are auctions, most buyers are prepared to wait for them to finish..........or they'd find a seller with buy it now if they want it straight away.

Edit: If you don't have time to list during your work weeks, you can always schedule them to start on your work weeks. You could schedule to start one or 2 each day/night. Then you can relax a little bit more on your week off.