Should grandparents be paid to babysit their grandkids?

My wife and I have two kids and we’re grateful that we both have parents who are close to us and are willing to babysit our kids a few days while we’re at work. On the other days, the kids are at daycare.

After talking with an older colleague at work, she says that she expects her kids to pay her to look after the grandkids. Her rationale is that she is effectively providing a daycare service and should be paid for it.

Now we don’t pay our parents like daycare fees, but we do cover any costs involved (ie food and outings) and we also gift our parents occasionally as a way of saying thank you.

Financially it probably works out to be equivalent, but the idea of ‘paying’ our parents as opposed to gifting them seems odd. So, should grandparents be paid to babysit their grandkids?