I am using a 42 year old bun bun. She is 5'2" & around 130lbs. She eat a lot, and always sweating in the summer time. However, she can carry heavy things. It's good because BB always needs carrying.
She needs to sleep a lot. She doesn't wake up when thunderstorm or baby cry. I go to BB room to take care bb, but she is still sleeping.
I think it all depends on her physical ability. My first maid is 40 and she is VERY strong. My second one is also 40 but she is as weak as a piece of paper....