Not only am I the person my colleagues, friends, and family go to for IT advice about services, hardware, apps, and devices, but I also get questions from those I know who work in IT.
Just today, I had this conversation with a friend who now runs her own business but used to be on-campus tech support for the school district I worked for. She knows her stuff, but knows I’m a reliable resource for IT knowledge.
You don’t really want to buy laptop batteries from just anywhere so you know they’ll work properly (and not catch on fire). I recommended ifixit because it has quality parts for sale and guides for fixing Apple (and other) products.