Many parents carefully consider the number of months or years between each of their children. Others choose to play it by ear. Still others find their plans upended by surprise pregnancies or multiples. Regardless, moms and dads tend to have lots of questions when it comes to spacing out kids: Will having them close in age cause excessive bickering? Will having them farther apart mean they won’t become close friends? Can we handle having multiple small children at once? If I wait several more years, will my age cause complications? Can we afford another child right now? Do we have enough space?

The answers will vary from family to family. “Forming a family and deciding how to space children out is a very personal matter,” says Dr. Susan Klugman, an obstetrician and gynecologist at Montefiore Medical Center. But when considering timing and children, medical professionals recommend first taking into account the health of both mother and baby. Klugman points out, for example, that “there is a higher incidence of preterm labor” among moms who conceive within a few months after giving birth, and recommends women wait a full year before becoming pregnant again, “just to allow your body to heal.” Once a mother becomes pregnant again, Klugman advises she stop breastfeeding. “When you’re nursing, you can get uterine contractions, so there is an increased risk of miscarriage,” says Klugman, who also heads the Division of Reproductive Genetics at Albert Einstein College of Medicine.

A 2006 study in the Journal of the American Medical Association, entitled “Birth Spacing and Risk of Adverse Perinatal Outcomes,” concluded that the ideal time for conceiving a subsequent child is between 18 and 59 months after birth. Excessively short or long inter-pregnancy intervals, the study found, came with increased risk of preterm birth and low birth weight.

Cathy Jo Cress, parenting and family lecturer and co-author of “Mom Loves You Best,” a new book on sibling relationships, maintains that parents’ emotional readiness is also a crucial factor. “Spacing depends upon what the parent can bring to each individual child,” Cress says. “A mother and father need to think about the amount of emotional support they can give the subsequent child.” What’s more, “sibling rivalry happens pretty much with all very close siblings,” Cress points out, and even parents of children three to four years apart will agree that sibling rivalry is simply an unavoidable part of most families’ lives. To mitigate it, Cress recommends parents “encourage positive activities that siblings can do together,” and shower equal amounts of love and attention on each child.

Judy Capano, a mom living in Manhattan, was happy to have her two oldest children close together. Her first, a daughter, is now 10 and a half, while her son is nine: a 17-month difference. “I have observed a lot of my friends and sisters having children that were two and a half years apart, and that’s a very difficult split,” Capano says. “What happens is you have a two-year-old, and you’re chasing them around when you’re pregnant, and then you have an infant.” Capano’s daughter was just eight months old when she became pregnant again, and “she was only just starting to get moving.”

Now that they’re older, Capano says the two children get along for the most part, but sometimes the short age difference causes a little friction. “It’s a little too close for my daughter sometimes,” Capano says. “She’s doing something and he wants to do it just at the same time.”

But both her older children adore her youngest son, now five. “It’s a nice spread; there is enough space that he’s not in their stuff,” she says. When her youngest son was born, her older son was three and a half. “He was out of the stroller, he was completely toilet-trained, he was more independent, so I just really had one baby then,” Capatano says.

Parents have children five or more years apart for any number of reasons, both planned and unplanned. Some couples want to avoid the stress of having multiple small children in the house. Some suffer miscarriages that prolong the age difference between children. Some divorce and remarry over a number of years. Some simply choose to enjoy extended periods of time with the child or children they currently have.

Like having children close in age, choosing to space out children five or more years apart has its own predictable effects on the family dynamic, Cress says. Sometimes siblings with several years between them will each be treated as “single children,” enjoying plenty of attention from parents at all stages of their development. Parents may want to encourage siblings who are spaced farther apart to build a strong relationship by participating in activities together, as “many times they will fall into this category of ‘listless siblings,’ where they don’t have a lot of contact.” While siblings with a significant age gap can become estranged as adults, Cress notes that her own two grown daughters, who have an 11-year age gap, “are thick as thieves.”

For Randi Jacoby, an Upper East Side mom and pediatric speech pathologist, having her two sons six years apart has been a dream. “They have a very close relationship,” says Jacoby of her children, now ages 16 and 10. “My younger son idolizes my older son, and my older son adores his younger brother.” What’s more, their distance in years means that “there’s no competition and there’s no rivalry.” Though her oldest was only six years old when his brother was born, their relationship evolved over time into one of care and affection, and now “he’s almost a surrogate father at times.”

Whatever your children’s age differences, Cress encourages parents to plan regular activities for the whole family. Hold family meetings, and expect all family members to pitch in when it comes to household chores. “It’s about making a team,” Cress says, regardless of how young or old each member may be.

Ultimately, having children is always a leap of faith, and your children’s unique personalities and needs will influence your family dynamic just as much, if not more, than how far apart in age they are. And whether your children are one or 10 years apart, Cress says, “You just learn how to spread out the love—and limited energy—you have.”