How to refresh listings
In this industry it is important to ensure your listings do not stagnate. As your listings become older, they slowly go down the search and become less visible. Promoted listings can offset some of this loss of rank but organic rank is very important to have a successful account, especially when you have less than 1000 active listings.
You should aim to have a listing cycle where all listings which have not been sold or are not performing well are replaced by new ones. Not only will this increase your average search rank as new listings rank higher than old listings and appear with a "new listing" icon, it will also reduce your reliance on promoted listings which will increase your profitability.
This cycle can be a monthly cycle or a three monthly cycle, it is what works for you, but ensuring you have some set plan can greatly increase your sales and profit.