But now it's been revealed just how much of a sacrifice the older generation are making for us and their grandchildren.
In addition, it's increasingly the norm for grandmothers and grandfathers to spend at least £1,000 a year on their grandchildren from their own pocket.
The study commissioned jointly by Grandparents Plus, Save the Children and the Family and Childcare Trust, also found strong support among the public for grandparents who still work but have caring responsibilities to be entitled to unpaid leave.
Sam Smethers, chief executive of Grandparents Plus, said: "This is generation generosity in action. In addition to the care they provide, grandparents are making huge financial contributions to support their grandchildren.
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"It suggests we need to rethink working requirements for the ageing population, who are being expected to work longer and care more for grandchildren. This simply isn't sustainable.
"Grandparents are a hidden army of carers giving a lifeline to parents who need to get back to work and who often cannot afford childcare.
"They need our recognition and support. This poll shows millions have cut their hours, taken time off or days off sick, or stopped working altogether to take the pressure off their own children.
"But it also shows a majority of public support to find ways to ease the pressure for grandparents, such as unpaid leave."
Polling by Ipsos MORI, found that 14 per cent of grandparents – the equivalent of 1.9 million people – said that they had given up a job, reduced their working hours or taken holiday or even sick leave to babysit for their children.
Twice as many grandmothers polled as grandfathers said they had done this.
Four in 10 of those who care regularly for their grandchildren say they do so to enable their children to work but almost one in five said it was because their children could not afford childcare.
The survey also suggested that about 1.6 million spend more than £1,000 a year on their grandchildren while the equivalent of another 2.3 million say they spend between £500 and £1,000.
Meanwhile 59 per cent of the wider public polled supported the idea of grandparental leave to look after a sick grandchild and 51 per cent support unpaid leave for childcare.