I love coaching. That's one of the reasons I went to instruct beginning track drivers with NASA. That moment when you see the lightbulb go on, and they get that look on their faces saying "Oh, now I get it!" -- that's what makes it all worthwhile to me.
It is also cool to see my former students at later events, graduating to advanced groups, getting faster and more comfortable on track. Knowledge that I have contributed to a lasting passion is really cool. They may be cursing me later for getting them addicted to the very expensive crack pipe of going fast, but they will be grinning ear to ear while burning through that cash!
I am usually generous with my knowledge and see no reason to not share if someone asks for help.
Sometimes however I think that the advice the person is asking for is not the advice they actually need. Let me tell you a story.
A friend of a friend who I haven't met yet is about to launch a community site for their startup, and asked me to help with some advice and pointers how to make an online community succeed. The community I run has been around for a long time, and I can't claim all of its success, but it sure works, and I have learned a few things about why it is as popular as it is with our users. As is my custom, I emailed back saying that yes, I would be glad to help.
The person asking me for advice proceeded to say, they were available for a conversation in San Francisco, SoMa district. Seriously? Call me old-fashioned, but this is not the way to ask someone for a favour. When I ask someone to help me out and they agree, I usually ask the other person when and where they will be available, and go meet them there instead of offering them options to meet me on my schedule.
Finally, we agree on a time for a phone call, but when the calendar invite arrives, it's for an entirely different date!
I am afraid the person is not going to like my advice.