The financial lives of adult children and their parents have become more intermingled in the wake of the financial crisis, but the two generations differ when it comes to talking money.

According to the Intra-Family Generational Finance Study from Fidelity Investments, almost two-thirds of survey respondents are at odds as to when to have financial conversations.

Parents prefer to wait until after retirement, while their children want to chat well before their parents leave the work force or experience health issues.

This lack of coordination means families aren’t making crucial financial decisions until it’s too late.

“A lack of conversations creates a lack of information, which makes it challenging to successfully navigate all the dynamics related to retirement and aging parents,” says John Sweeney, executive vice president of retirement and investing strategies at Fidelity. “Many adults who are nearing retirement don’t know how to fund their own retirement and it creates a significant amount of anxiety for adult children.”

The disagreement between adult children and their parents doesn’t stop at when to hold financial conversations. The survey finds adult children think their parents worry about financial security far more than they actually do.The survey shows 56% of adult children think their parents worry about financial security. In reality, 23% of parents report worrying.

What’s more, adult children underestimate the value of their parents’ estate by more than $300,000. There are also disagreements about who will care for a sick parent. Close to half of adult children plan to step in, but 6% of parents expect this help.

“Admittedly, these discussions aren’t always easy, but there can be real emotional and financial consequences when they don’t happen or lack sufficient depth,” said Sweeney. “It’s absolutely critical families take the time and break down any barriers that may exist.”

He advises families have ongoing conversations that should start before the parents retire, pointing out that 70% of new retirees don’t know how to manage their finances.

Nearly all survey respondents who discussed estate planning say it brought a greater peace of mind, while 73% report it would help their children’s emotional state of mind as well.

Sweeney says adult children also need to follow the “voice, not vote” rule during the conversations. “While family members should have a role in the planning process, make sure the ultimate decisions made are consistent with the dreams and wishes of the parents who have worked hard building up their nest egg and deserve to chart their retirement destiny,” says Sweeney, noting that “life is not a democracy.”

Who conducts the talks also matter. The super controlling sibling might not be the best choice to lead the discussion, but neither is the overly laid back family member. Sweeney recommends defining people’s roles, conversation topics and who should be involved before the talk gets underway.

Following up and keeping the conversation going is also extremely important. “These conversations are not ‘once and done,” says Sweeney. “Keep the momentum going and schedule as many get-togethers as you need—and revisit the plans you make at least annually, to make sure they still make sense.”