Tipping babysitter

[ConnecticutNonna]

Has anyone used childcare services?
We have arranged for childcare at CR while we are at MK for an almost 4 y/o while we attend DAH.
How much should we tip? Does it go by total cost, or by hours?
Thanks for any help!
TIA

 

[kandb]

20%?

 

[ConnecticutNonna]

20%?

Yeah, that was my first thought... But, didn't know if it was generally a dollar amount.
Thanks