The companies in this article were included in the Entrepreneur360™ Performance Index.

Part of the appeal of running your own business is that you get to hand-pick exactly who you work alongside each day. But let’s face it: it seems as if no matter how much you vet each candidate, you never quite know what you’re going to get.

The hiring process is challenging, especially for newer business owners. Determining whether an interviewee is well-suited for the startup environment is just the start. You must also consider whether they’d fit your company’s culture and core values, then take extra steps to ensure they’d complement your pre-existing team.

That’s why we asked a range of startup founders featured in the Entrepreneur360™ Performance Index their top, go-to question for potential candidates. Check out what they ask during job interviews and whether you should ask your potential hires the same thing: What's the one question you always ask when you interview someone? Why?

“If you didn't have to work, why would you come into the office?”

-- Gautam Gupta, co-founder and CEO of NatureBox, a monthly subscription service that delivers healthy snacks.
Why: I try to understand the person's motivations and interest.I also try to understand where they want to take their career and how NatureBox fits within that path. Lastly, I'm looking to gauge their intellectual curiosity.

“What are your career goals over the next 3-5 years?”

-- Matt Straz, founder and CEO of Namely, a cloud-based platform that helps businesses manage payroll, benefits and other HR needs.

Why: Millennials are leaving their employers twice as fast as those from older generations, making average tenure in a job about three years. With that said, I look for hiring opportunities that could surpass that time period. We invest in the employee’s development to keep them motivated to do great things because it aligns with their long-term career goals-- which is a win for the company.

“Why do you do what you do?”

-- Joe Coleman, co-founder and CEO of Contently, a software business that helps companies build audiences by managing the workflow of premium marketing content at scale.

Why: By the time I interview someone, several people whose opinion I trust have already signed off on them, so I’m really just trying to get to know the candidate. I try to get a sense of why they do what they do, their background, and what motivates them. At the end of the day, it’s really important to hire people who contribute to the culture in a positive way.

“I don't ask questions; I talk to them.”

-- Jamie Siminoff, CEO and chief inventor of Ring, the maker of the Ring Video Doorbell which allows users to answer the door from anywhere via smartphone.

Why: I want to socially understand them, learn what their interests are and see if they are a cultural fit. I think asking typical interview questions can be like a game, but social interaction is much harder for someone to rehearse.

“It isn't so much a question, but rather we always look to see if the person across the table has a passion for their field.”

-- Aaron Firestein, co-founder and chief artist of BucketFeet, an online retailer that collaborates with artists to design and create footwear.

Why: It’s important for employees to have a commitment to our overall goal of bringing people together through stories and art.

“Tell me a brief version of your life story.”

-- Gabriel Weinberg, founder and CEO of DuckDuckGo, a search engine that focuses on user privacy and doesn’t track your searches.

Why: This reveals how they view themselves and what is important to them. Their answer can be used as a guide for the rest of the conversation, jumping off from various things they say.

“What do you like -- and don’t like -- about Birds Barbershop?”

-- Jayson Rapaport, co-founder and co-owner of Birds Barbershop, a brand of salons that markets affordable, high-quality cuts and color services. The company recently launched a line of hair care products.

Why: I learn whether they’ve had any sort of relationship with Birds. If they’ve never been, have they spent time understanding what we’re about? They’ve either done their homework or they haven’t.

“If you were given $1 million dollars every year for the rest of your life, what would you do?" After an answer, I ask "Ok so you've done that, what would you do next?" and continue asking that until they can't think of anything else.”

-- David Simnick, co-founder and CEO of SoapBox Soaps, a maker of all natural, handmade soaps that donates soap products to children in need.

Why: Usually the last answer or two shows what the person really wants out of life and tells me what they care about the most. It helps me understand what motivates them.

“Who were the competitors at the last company you worked for and how did your company differentiate itself?

-- Ian Siegel, co-founder and CEO of ZipRecruiter, which lets employers post jobs to hundreds of job boards with one submission and sends job seekers postings via tailored email alerts.
Why: I want to determine if the candidate had a strategic understanding of the business. Surprisingly few candidates can answer this question. I am especially impressed by candidates who have a grasp of existing competitors, potential competitors and what a disruptive, new market entrant could do.

"Why Shoptiques?"

-- Olga Vidisheva, founder and CEO of Shoptiques, an e-commerce destination that sells goods from local boutiques.

Why: We only hire people with a clear enthusiasm for what we do, because those are the only kinds of employees who will help you innovate and who can grow with your company.

Related: What Keeps You Motivated? 8 Entrepreneurs Explain How They Manage Through the Ups and Downs of Startup Life.