Not every new hire is a keeper. Here’s how to take a clear-eyed approach to assessing the latest additions to your team—and when to cut your losses.

You’ve probably heard the conventional wisdom about bringing on a new employee, “Hire slow, fire fast.” As a piece of advice, it checks the boxes: clear, practical, tough-minded and simple. HR consultants swear by it, as do working designers. But as anyone who has had to evaluate a new employee knows, the phrase is easier to recite than it is to live by. Exactly how fast are we talking here—do you fire someone the first time they drop a pen?

Hiring a new employee is a big step, whether they’re your first or 10th. You’re welcoming someone into the world of your firm, trusting them to represent your business, and taking on a financial burden too. In those first few months, the relationship can be fraught; it’s easy to oscillate between expecting too much and excusing too much. The tendency to want the new person to work out is strong, and ego can come into play—after all, you chose them. But some hires simply aren’t going to work out in the long term. The trick is knowing how to tell.