I am what you call a "boomerang" entrepreneur. I quit my job to become an entrepreneur and it didn't work out the way I wanted it to, so I got a full-time job. But something inside me said I had to try starting a company again. So I quit again, and you're not going to believe what happened: I failed--even worse than the first time.

I got another full-time job, this one as a marketing director. It was the first time I led a marketing team instead of a technology team. I used that experience to try entrepreneurship for a third time. This time, it worked well.

The term boomerang entrepreneur means I keep coming back to entrepreneurship. Every time I come back, I come with a newfound respect for entrepreneurs and the grind we go through every day. Many entrepreneurs give it a try, figure out quickly that it isn't going to work, and then get a full-time job forever, but that doesn't have to be you. 

So, if there is one person who knows about how to prevent your entrepreneurial career from peaking, it's me. Here are my three tips on how to have a longer entrepreneurial career. 

1. Know that you're company doesn't need to get acquired for you to be successful and happy.

If the only metric you use to measure your happiness is whether you get bought out for eight or nine figures, find another metric.

Intimate relationships with your partner, family, friends, or kids can make you sincerely happy. No company can do that. Harvard's happiness expert, Daniel Gilbert says, "We are happy when we have family, we are happy when we have friends and almost all the other things we think make us happy are actually just ways of getting more family and friends."

As for happiness at work, do activities you care about, lead a team of people you love, and earn enough to live on. Those factors, not the fact that you typed "founder" in the signature line at the end of your email, will make you happy at work. 

2. Remind yourself that you have time.

No one gets to be a prodigy forever, but that's okay because once you quit being the smart, young person at work, you're primed to start your own business and hire other smart, young people to work for you.

The average age of a "successful entrepreneur" is much older than you think -- 45 years according to the Harvard Business Review. That's as true for founders of high-tech startups as it is for people who bootstrap a local pizzeria or dry cleaner. In complex industries, the average age even goes up to 47, and Colonel Sanders was 62 when he franchised KFC. 

So if you're thinking you're too old to start a business, you're probably not. In fact, work experience is key to making your entrepreneurial enterprise succeed. If you stay out of debt and stockpile your savings in your 20s and 30s, then once you hit 40, you're in good shape to take some risks. Stay in good financial condition to cushion the impact of any dips your new business might experience. Build a strong professional network. Start your own company. It's the perfect over-forty pivot.

3. Therapy can go a long way. 

Tech entrepreneurs peak and decline much earlier than people in other professions. It's not uncommon for a former tech whiz to feel washed up at age 30. Hitting a slow patch in mid life is nearly certain for early bloomers, but if you feel like that slow patch is turning into a slow-motion crash, get help.

And plan now so that when--not if--your first venture peters out, you're ready to find a new career, a solid relationship, or a personal mission to invest your energy and intelligence into. If you're like most millennials, you'll work in seven to ten careers before you call it quits. Eventually, people won't just allow you to have more than one career, they'll expect you to have multiple careers. You could live through several full entrepreneurial cycles from one-person startup to full-on executive during your working lifetime. 

I've gone through the boomerang entrepreneur cycle of full-time work to entrepreneurship and back again more than once now. I know how rewarding starting your own business can be, and I know how easily it can fail. So if your first effort at starting a business collapses, you can try again. Work full-time for a while if you have to, but don't give up. You're just positioning yourself for a better run next time.