Just like you shouldn't take cooking advice from a skinny chef, you probably shouldn't accept business advice from someone who has never run their own business.
A number of years ago, I went to the bank to obtain an operating line of credit. Upon showing up for my appointment, I was directed to a closed-door office where someone was waiting to talk to me via telephone.
The person on the other end was a small business advisor who asked me some questions about what I did, how things were going and why the line of credit was being requested.
I explained my reasons (which is that I sucked at cashflow planning and couldn't pay myself for the next two months) and we talked a bit more, and then out of interest, I asked if they had ever run their own business. The person responded No and soon after, changed the subject. I could hear a difference in their voice from that point forward; they were less confident and authoritative.
In that instant, I knew they didn't understand. They had no idea about the everyday struggles, stress, complexity and fatigue that comes from starting and running a business of your own. That's fine too. This is why full-time jobs exist. I have no problem with those that have them (I dream of it myself quite often) but I don't think you should be doling out strong business advice to someone if you've never lived through the experience yourself. Unless you're an extremely wise and gifted, empathetic person, you will never get it.
Today when I talk to small business owners, the conversation feels a lot like therapy. When we openly share our ups and downs, our hardships and successes, we feel that invisible bond of business ownership. No matter if you're selling knowledge, services or products, the core experience is universally the same.