Parents sometimes have unmet expectations of their children, like forgotten chores, a different career path, and in extreme cases, taking care of them in old age.

But when those caregiving expectations between parents and their children are misaligned, it could be disastrous — emotionally and financially — for both parties involved. Parents are left with no one to help them around the house or bring them to doctors, adult children save less for their futures as they help pay for their parents’ care and, in a few scenarios, may cut back on work hours or leave a job altogether. What’s worse, these conversations may go undiscussed until it’s too late.

See: Money Milestones: How to manage your savings once you become a parent’s caregiver

Karen Van Voorhis, a financial adviser at Sapers & Wallack, saw this firsthand when she and a client well into his 70s were discussing where his wife would live when he passed. The client, who had a few houses, said his wife would move into a cabin, but one that required maintenance such as feeding a wood-burning stove and shoveling snow. When Van Voorhis asked who would do this upkeep, he said his son and daughter-in-law would move in with the mother — except they never discussed that and his son was unaware of this expectation. “I was shocked that was a conversation that hadn’t even taken place yet,” she said.

More than 55% of parents anticipate their children will be the ones caring for them, physically or financially, as they age, according to a survey by Bay Alarm Medical. But not all children agreed with that notion, or knew about it. In some areas, like the Midwest, only 36% of people felt children were obligated to care for their aging parents. Participants in other regions of the U.S. were much more likely to say they felt an obligation to caring for their parents in their old age. Parents are more likely to lean on their daughters (and expect that of them) than their sons — about three and a half times more so, actually, according to a 2006 study on mothers’ expectations of caregiving by their children — and usually rely on the children they feel are closest emotionally.

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But families don’t talk about this, or most money topics, because they’re so uncomfortable or private. Not only do parents keep their finances hidden, but they sometimes forget or avoid, or just don’t know how, to tell their children what they expect in their old age. The consequences could be a disappointed parent, or one without the proper plan to fund their care. Children meanwhile bear the brunt financially if they become their parents’ caregiver without planning, said Edward Kramer, a financial adviser at Abacus Planning Group in Columbia, S.C. The children may not pursue the careers they want because they have to move back home, or they won’t put more money in a retirement account because they think they’ll need liquidity for when their parents fall ill.

“Communication is vital between the generations in terms of caregiving, estate planning and myriad other reasons,” Kramer said. “Communication goes a long way to help both generations plan and live without regrets.”

So how can families begin these talks? First, get the entire family together (or at least those most important to planning) and come up with a list of questions or concerns, such as who will provide physical care, do household chores or pay bills, according to AARP. Because this is such an emotionally charged subject (people don’t normally like talking about their declining physical or mental state), children have to be especially patient and empathetic toward their parents, and give them room to get angry when they bring up difficult observations, such as impaired driving abilities. If parents keep resisting the conversation, be persistent and bring it up as many times as necessary.

Also see:This is the one thing you must do if you’re caring for someone with Alzheimer’s

The good news is this: Children caregivers tend to step up to the plate, even if it is a stressful situation. Of all the 2,000 caregivers surveyed in a Merrill Lynch and Age Wave report, 100% said they support their loved ones emotionally and socially, followed by 92% said they provide household support, 84% who said medical support and 64% who said physical care. Another 92% said they provide financial assistance, such as paying the bills, handling insurance claims and cutting back on their own expenses or dipping into their own savings accounts. When there are siblings, it helps if they discuss this separately and assign a point person if not everyone is available to help mom or dad. In some cases, that point person may be paid through the family’s funds set aside for caregiving. “Someone’s time is valuable, and to acknowledge that smooths any feathers that may be ruffled,” Van Voorhis said.