A friend of mine is an entrepreneur in his mid-30s. His business is almost four years old, and it's growing well, though it still is not profitable. He and his wife chose to live near the nexus of two interstates -- a grim, realistic nod to his life on the road. She is 36 now but plans to wait to have kids until he is home more. I understand her fear of being widowed by the business and of raising a child with no money and no security. But if she waits for the right time to bring a baby into the world, she will likely welcome Junior along with her first AARP card.

The reality is that when you are entangled in an entrepreneurial life, there's never a right time -- for anything. There's no right time, because there's no time (and usually no money, either). For having kids, for buying a house, for getting a dog, for taking a vacation, for going out to dinner. Planning becomes difficult when income (if it exists at all) is insecure and savings are usually (to put it gently) unsubstantial. No matter how loudly private life calls out for investment -- of time and of money -- the business screams even louder in its demands for both. An entrepreneurial life becomes all about postponing -- "When we break even…," "When we get that contract…," "When we hire that salesperson…" -- ah, yes, that's when our lives can move ahead.

The fact is that while you are building (and building, and building, and sometimes rebuilding) a business, you are also composing a life. With apologies to John Lennon, life is what happens while you are busy making a five-year plan. All you get to decide is how, when, and especially whether you are going to craft it. There are personal opportunity costs to starting a business if it causes you to postpone making a life. This is especially true if family and business are young at the same time. Put off having kids too long, and you may end up with fewer than you wanted or none at all. Put off taking vacations and going out to dinner with your spouse, and you won't create those memories and points of connection that glue a relationship and family together. Put off exercise, and you may irreversibly damage your health.

Theoretically, entrepreneurs control their lives and schedules. But the exact opposite is usually true: Entrepreneurs are whipsawed by their businesses. There is a constant sense of crisis, and every aspect of running a business demands more time than there are hours in a day. If the entrepreneur doesn't build a high wall around his or her personal life, the business is sure to overwhelm it.

But how can you create a personal life when you can't even plan a day? Entrepreneurs often don't have the financial stability to erect the bulwarks of a normal life -- taking out a mortgage, depositing into a college savings account and a 401(k). Their paycheck is one of the first things they sacrifice when times are tight. How is it possible to build a solid home on such an insecure foundation?

My husband, Gary, and I had a young marriage and a young business at the same time. We learned early on to relinquish any sense of control over either one. In our personal life, we planned nothing at all. We had our first two kids in a rented farmhouse that was freezing and dilapidated. Our fledgling yogurt business, Stonyfield Farm, was a liability, not an asset. Our economic future was bleak. We lived in the country with very few friends around. We would stand next to the roaring refrigeration compressors to lull our colicky babies to sleep. It was chaotic and more than a little pathetic. Never mind paying for college -- where was the money to fix up the baby's room?

We took vacations we couldn't afford and paid off the Visa bills for a year afterward. I remember making copies of the credit card statements for Gary and writing "HELP" on them in big letters, as if he could magically convert 50-cent yogurt coupons into cash for our minimum monthly payments. But we took those trips and did other things we could ill afford because we knew we had to keep living and squeezing as much joy from life as we could under the circumstances. We had forsaken any traditional sense of normalcy and had utterly abandoned any notion of security. Before helping found Stonyfield, our partners Samuel and Louise had for a time lived in a wood-heated barn with their six kids; the children nestled together at night in sleeping bags in the loft. Compared with that, we felt bourgeois in our ramshackle farmhouse. I will always be grateful for the courageous example Samuel and Louise set by their refusal to tie life decisions to the ebb and flow of business.

Gary and I managed to separate our reactions to our business situation (depressed) from our feelings about our personal future (optimistic). He may have had all his fingers in the dike, but intuitively I knew that I shouldn't spend my time piling sandbags. We never fooled ourselves that someday would come and that we would reach a certain place in our business that would permit us to progress with our lives. In reality, a business never grows up. It may reach a point where it no longer needs constant coddling, but it's an evolving organism that constantly challenges its founder, sucking up attention and resources at every stage. The intensity is relentless, and the work never ends. If you allow a business, even a successful one, to dictate the terms of your life, you will always find reasons to delay making the big personal decisions -- there's the new branch that is just about to open, that merger on the horizon. When businesses survive and thrive, it's the nature of the entrepreneur to keep expanding them.

In our case, Gary and I now have no worries about retirement, and the kids' college educations are covered. Our business is successful, and we are in a position to enjoy the fruits of financial security. But after Stonyfield took off, Gary got into more mischief. He started another company, an all-natural fast-food restaurant. He began producing organic yogurt in Europe. He travels frequently and is more overcommitted than ever. Now that the kids are almost out of the nest, I'd like to take trips with Gary for pleasure, not for work. I'd like us to garden together and get really good at swing dancing. I'd like to create a less frenetic life. But it looks as if that's got to wait; until when, I'm not exactly sure. Now is not the right time.

Meg Cadoux Hirshberg is married to Gary Hirshberg, president and CEO of Stonyfield Farm. She writes a regular column about the impact of entrepreneurial businesses on families.