I spend most of my time in the Collectibles board, but I would imagine this would apply to any Marketplace board..

If you list an item that doesn't sell, give it a couple bumps and move on (to Ebay/Offer UP/Craigslist etc). There is limited space on the boards, and continuously bumping items for months and even years on end is only clogging up the boards valuable space (I'd also recommend looking up the definition of Insanity).  This is especially relevant for the Collectibles board when you're listing items that aren't 100% on topic (not cryptocurrency related collectibles).