I remember reading Nords' advice based on his actual experience, so I have been very vigilant with other people making demands on my time during my 3 months of early retirement so far.
One request from my SIL was "hey, can you drive across town, pick up my daughter from school each afternoon, help her with her homework, feed her, and I'll pick her up a few hours later". I was honest and said "I have 3 kids of my own, so I'm pretty busy. I also do things in the afternoon sometimes where I'm not available. And I normally walk to pick up my kids, so your daughter would have to walk with me."
That killed round #1 of requests. Then the kid starts failing in school. So my wife, in her infinite generosity with my time (grrrr...), volunteers me to "help with tutoring" with the understanding that the kid will be dropped off at our house each day, and I'll try to let my SIL know when I'm out and about and won't be there to receive the kid. So far so good. I'm usually pretty busy in the afternoon time period with my own children, catching up on chores around the house and/or relaxing/playing/creating on the computer. So there hasn't been a lot of tutoring going on, but at least my niece has a quiet place to do her homework (instead of a house filled with beaucoup screaming children where she was before). Hey, if I suck at tutoring, you can fire me any time! ;)
Otherwise, I haven't had many requests. I guess I have the "I have 3 kids and I'm pretty busy with them" excuse. It'll be interesting once they are all in school and I'm free from 8:30 to 2:45 every day. The main point is to be generous when you want to, but don't leave a life of well paid employment to become somebody else's bitch. You earned ER from hard work and savings. Live your life like you want to.