I was speaking with a budding young entrepreneur recently who I’ll call “Wolf,” and this was one of the many good questions he asked me about a venture he’d like to start:

“I keep hearing that I need a co-founder, but there’s no one that I really want to work with. I haven’t met anyone I really trust with my idea. I either don’t trust them as people or I don’t think their work is going to be the right quality for what I want to do.

Do I really need a co-founder?”

As I told Wolf, the bottom-line answer is this: No, you don’t NEED a co-founder. And certainly there are plenty of successful entrepreneurs who have not had a co-founder, including Jeff Bezos of amazon.com, Susan Blakely of Spanx, and Pierre Omidyar of Ebay. Going back further, a couple of little startups called Wal-Mart and FEDEX were founded by the solo entrepreneurs Sam Walton and Fred Smith, respectively.

But keep this in mind: Almost all investors have a strong preference for founder teams of two or more, and a belief that those teams have a higher likelihood for success.

Why?

1. The Workload. Startups are hard work. Really hard work, and if your startup is growing like it should, it’s almost certainly going to be beyond the capacity of single person any day now.

2. The Skill Sets. Related to that, unless you’re Superman, Batman and Wonder Woman all rolled into one (with some Spider-Man thrown in for good measure), you do not have all the skills necessary to make your startup a success. Most successful startups are built by teams of co-founders with complementary skill-sets. Think Jobs and Wozniak, Larry Page and Sergey Brinn, Bill Gates and Paul Allen, Bill Hewlett and Dave Packard,… the list goes one and on.

3. The Disagreements. You need someone who knows the business as well as you to disagree with you. It’s actually no good to have a co-founder who thinks just like you. You need someone to bounce your ideas with and put them to the test. It makes for better decision-making.

4. The Emotional Support. As we’ve covered, startups are hard work. The highs are high, the lows are low. Your co-founder is going to be the person who you’ll be sharing those times with at 3 in the morning over cold Chinese food.

Do you have a co-founder? Are you looking for one?