If you're hoping to assist your kids and grandkids, it's important to get your own financial plan in order first. Think about how that outlay of time or money will affect your ability to meet your own financial goals, whether that's exploring an encore career or traveling, said Douglas Boneparth, a certified financial planner and president of Bone Fide Wealth in New York City.
"It's your grandchild, but you can't escape the fact that [caregiving] is still work," he said.
Nearly half of grandparents in the TD Ameritrade survey said they have made at least one compromise to provide that time or money support for their grandkids. More than a quarter have dipped into their savings, while 15 percent "spend less time enjoying life" and 8 percent have postponed retirement.
Even if you're willing to make such compromises, make sure the help you provide won't put you at risk of needing financial support yourself down the line.
"Do you want to spoil your grandchild rotten at the expense of running out of money at 80?" Boneparth said.
Think about the best tools to help, based on your ultimate aim, said Andrea Blackwelder, a certified financial planner and a co-founder of Wisdom Wealth Strategies in Denver. That may not be handing your adult child cash.
Contributions to a 529 plan could help you snag a tax break, for example, while direct payments to a medical provider to cover health expenses are exempt from gift taxes.
Create an open dialogue with your children, Lynch said. That can help ensure the whole family benefits from your help.
"That way there's clarity on what the expectations are," said Lynch. "You hate to see money tear a family apart."