In our family, my Uncle Mike is something of a Wikipedia on many subjects, mostly dealing with practical knowledge. Like, if you're trying to figure out whether to buy a special air filter to help you with your allergies, he'll tell you that you can buy a 20" box fan, a 20"x20" high quality furnace filter, tape that to the intake side of the fan, turn it on high, and you'll get the same effect as a high end HEPA filter. And when allergy season is over, you can take the filter off so you can use it as a fan.
He's full of neat facts like that. We call him when we're considering a new furnace purchase, debating the merits of a heat pump, wondering about the best place to plant blueberries, how to regulate the temperature on a wood stove, and whether an SUV makes sense if you don't live on a gravel road. He's the kind of guy you can learn a lot from.
I recently made friends with another guy like that, only his area of expertise is bicycles. His name is Ross Willard, and he runs a local charitable group, Recycle Bicycle of Harrisburg. You can ask him a question about any model of bike, any gear type, any brake type - he'll tell you exactly how to maintain and fix it. He's even more knowledgeable than the local bike shop guys (shhh - don't tell them I said that!).
I've known people you ask about herbs and essential oils, my brother sighs every time I call because he knows there's usually a computer problem I'm begging him to deal with, and my own husband is the guy people call when there's an issue with electrical issues.
So it blows my mind when I'm considered an authority on a given subject. Yes, I wrote a book about saving money, but it's still a bit weird when someone tells me they did something because I said it was a good idea! I mean, I'm thrilled that my advice helps people, but being someone's cloth diaper guru surprises me.
For example, a friend recently contacted me about the most ideal, cost-effective cloth diapers for her 3 year old son, who has Down Syndrome. And it's not the first time I've been contacted by friends about a hard-to-find or hard-to-fit cloth diaper. I have a few topics like that where I can talk your ear off, like diapers and washing laundry by hand. (Yes, laundry can be a topic of deep discussion around here.)
So, when you have a problem, who you gonna call?
(Ghostbusters is always an appropriate answer.)