Never.
Here's why:
Number one: how do you know the person asking you the question hasn't already provided you with referrals or business? Most of the time when I ask that question, I get blank stares. The assumption is usually that this person has given you no business at all. That can be a false assumption. What if the person has already provided 10 referrals for you? Five referrals? Even a single referral?
Let's use 10 as an example. Say over a period of time, the person has referred 10 people to you. And let's say your lifetime customer value is $2,000. Is not answering that one extra question from that one person really worth losing $20,000? I point this out because usually this inquisitive person is not asking their fist question. When coaches bring up this individual, it's usually someone who asks questions over and over and over and over. There is a history being built here. The relationship has gone from this person not knowing who you are, to trusting you, and in time, to being loyal to you.
Let's assume there are no referrals involved and you tell that person to piss off- you're not going to answer their questions anymore. You've pretty much guaranteed you're never going to get a referral from that person. Not only that, but any time anybody asks that person about you, their response is not going to be good. There's never a negative in answering an extra question. There's only positives.
The second reason: realize for a minute that they decided to ask you. Look at the options that people have today to gather information. They can Google it. They can search it. They can read a million articles and sites. They can ask anybody else but they decided to ask you. Think about that for a minute. Instead of using the internet, they asked you. To them, your credibility is greater than the internet. Is that bad? That's something you should take pride in. It's an honor that you've put yourself in a position to be a person that somebody would look to as an authority. They're not asking people that they think are unqualified.
They're not asking the question to people who they feel are nobodies. They're asking you. It's an honor and should be treated as such.
Third: I see this all the time.
Coaches today are planting their seeds. They're watching and they're looking down for these seeds to grow. They'll water the seeds. They will nurture the soil. They'll kick back and rest, lean against the tree, sit on a bench, walk barefoot in the grass and then come back and water again, take care of the soil, maybe fertilize, water again, look down and see no growth.
Then they'll start asking around. They'll ask their buddy, "Man, are your seeds growing? My seeds aren't growing. What am I doing wrong?" They'll ask somebody else. "Hey man, how do you make these seeds grow? I can't get my seeds to grow. Maybe they'll even hire somebody to teach them, "Hey, how can I get these seeds to grow?"
Then they get frustrated because they're doing all of this work. They're planting the seeds, taking care of the soil, fertilizing, coming back over and over and nothing is happening. They get frustrated and think, "I should be paid for this. I'm doing all of this work and I'm not getting paid shit. I should be paid for the work that I'm doing, for the seeds that I'm planting."
Here's what they don't realize. That tree they're leaning against, the grass they're walking on, the soil that they're using, the forest near the trees they're trying to plant, they were all planted by those preceding them decades and decades ago, a time when there was no such profession as personal training. There was not a strength and conditioning coach profession. There was not a way for anybody to do online training. There were very few ways for anybody in this industry to earn a living training people. Today, there is because of the seeds that were planted decades ago.
We are reaping the harvest that was planted for us long ago. The seeds that we are planting today are not for us. They're for our children. They're for the people who will be taking our place decades from now. When you plant those seeds and you look down, you're not supposed to see the growth. You're doing it to leave future generations a better industry than what you came into. You came into an industry far better than that of those who planted the seeds you're reaping the harvest of. That's life. That's living. That's passing on. Now tell me again exactly why being asked too many questions is a problem please.
Finally, if you have a problem with this you SUCK! This is how I know: if you are a professional trainer or coach, you will have a system set up to handle these types of inquiries. You will have time set aside for your e-mails, messages, and questions from clients. You understand that this is part of the business and part of your legacy. If you are unwilling to engage with those who build your business and build the industry, and unwilling to help build it yourself, then you should probably get a different job.