What's one of the biggest mistakes a startup can make? Not cutting bait with a bad-fit employee fast enough. It's particularly true when your team is only a few people trying to build the kinds of bonds that will take them through the inevitable rough waters every company will have to sail through. That's according to Nancy Hua, cofounder and CEO of Apptimize, a Silicon Valley-based company funded by Google Ventures and Andreessen Horowitz which has helped companies like Vevo, GlassDoor and Hotel Tonight deliver apps and easily deploy and test changes. After having tried out lots of people in the process of building her 25-person team, she says she has deduced several key indicators that someone isn't a good fit.

1. The employee isn't hitting goals.

Every company should delineate objective metrics team members need to be striving for. If they're not meeting them, it's a problem. While it might be easy to set quotas for sales people, how to you define the bars engineers, communications people or admins need to reach? After all, inevitably problems come up that create dramatic stories about why things aren't getting done. "People need to own an outcome," she says. "Even if you really like the person of if they're trying really hard, if they're not hitting the goal then it's a disservice to not make a big change."

2. He isn't happy with his career trajectory.

Sometimes people--especially younger employees--don't know what they want when they sign up with your company. Perhaps they didn't understand what a job really was until they tried it out. Or maybe they want a promotion but it's given to someone else who's more ready. "If you can figure out a way for them to achieve their goal at your company, then definitely do it," she says. "But if you can't, then don't string them along."

3. She's not growing fast enough.

Because Apptimize is operating in the fast-growing mobile space, its employees need to be on their toes. "Every few weeks we have a totally new set of problems and as soon as we start getting good at something it's not the priority anymore. Or, as soon as we're good at it we need to get good at some other totally new thing," she says. "If you're not growing then you're being left behind."

4. There's no ownership.

Employees have different responsibilities depending on their role and seniority. For example, people just out of college are on a strong learning curve. You invest in teaching them everything, and in exchange you expect they're going to learn as much as possible, work hard, listen and level up as soon as possible. "If they're not working their butts off, and not listening to feedback, then they're not owning that relationship," she says.

5. The person doesn't inspire the rest of the team.

It's easy for people to get along when things are going well. But what about when you miss a ship date, lose a deal or have to meet an impossible deadline? "When that happens the only thing that keeps your team together, are people who love and trust each other and have each other's backs," she says. "You need  people who are harmonious or otherwise it causes fragility for when inevitably these problems happen."