As you build a steady stream of loyal visitors, you're going to want to regularly give them new items to choose from and purchase. If you don't, your site runs the risk of going stale—and shoppers will start to visit less frequently.
Don't panic! You won't need to dismantle your entire product line every few months. But you can shake things up enough to keep your site fresh simply by discontinuing older, poorer-selling items, and replacing them with new products, while always maintaining your core inventory. At the very least, change up the products you promote on your home page and feature throughout the site. As long as shoppers see changes happening, they'll continue coming back to see what's new.