With customers there's the added benefit of improving business relationships and building trust. If someone contacts me with a question, and I withhold the answer until they pay me, they're gonna feel cheated when they realise the answer was pretty straightforward. It doesn't matter if, technically, I'm providing a service and I'm within my rights to ask for compensation. That customer is going to hesitate to return in the future, because they now feel I just care about their money.
Being open, transparent, and helpful has the opposite effect, in my experience. The customer feels at ease with me, they trust my judgment, know that I'm looking out for them, and so are happy to return to me when they need something, and pay for the job.
Case 1: the person learned and became more autonomous. Fewer questions like this will be asked in the future. You have developed good will.
Case 2: the person expects someone else to do their work. That won't fly for long with me. Fool me once, shame on you. Fool me twice, and I will react. Friends and family members can land on the no-contact list. Employees can get fired.
Assume the best, but always prepare for the worst.
Never helping anyone with technical stuff unless you're getting paid (or whatever similar thing you can think of) is over-correcting for the doormats that can't say no