Eventually, every product line reaches its end. Maybe the manufacturer discontinues it. Maybe your customers have moved on. Or maybe you're sitting on a pile of devices that just won't move.

Here's how to know it's time to stop ordering: you've had the same stock for over 90 days, you've marked it down twice, and it's still not selling. At that point, you're not making money. You're just paying storage costs.

Do a clear-out sale if you can, or bundle slow movers with popular items. But after that, let it go. Don't reorder out of loyalty to a product that your market has already voted against.