I would maybe start trying it 2 or maybe 4 times a year but bimonthly would be too frequently. I like to buy new items more frequently but really wouldn't be looking to sell stuff more than once maybe twice a year.

With families I can see the need for this more often as the kids outgrow toys but with daycare you don't really want to get rid of toys because the next kids coming in will likely get use out of it.

What I keep in mind when selling is the effort-price ratio. For my bigger items I want to sell myself on kijiji because I don't to forgo the consignment pay. It takes more time and effort on my part but I get 100% of sales. Do you plan to charge a fee to be a seller? With items like clothing and small toys I consider a consignment or yard sale because those items are harder to sell online and require more effort than the profit.