If you’ve already invested a significant amount of time or money into something, it can be tempting to hold onto it longer than you should. And the longer you hold onto it, the more difficult it becomes to let go of, even when you know you should be heading in a different direction.

The time or money you’ve already expended are known as “sunk costs;” there’s no getting them back. But sometimes these expenditures of the past have an inordinate influence on what we decide to do in the present. Instead of making rational decisions based on where we’re currently at and where we want to go, we make emotional decisions based on what we’ve already spent (this flawed reasoning is also known as the “sunk cost fallacy”).

Instead of worrying about what’s already been spent, the key is to focus on 1) where we actually are now, 2) where we want to go, and 3) the skills, resources, and opportunities we now have at our disposal. What’s the best path forward based on these factors, and not what we’ve already spent? Sometimes staying on the current path makes the most sense. But other times, we’ll see that moving in a different direction is actually our best move.

A sunk cost is just that: it’s sunk. You can’t get it back. But that doesn’t mean these past expenses were a waste (often it’s this fear of a realized loss that fuels our desire to hold on). Regardless of whether they were good choices or bad choices at the time, there’s always the opportunity to learn from the experiences of past. And if you learn from them, they were not wasted. But learning from them is different than letting the sunk costs of yesterday continue to influence the decisions you make today.