There is a huge premium to be captured by consultants simply by eliminating the appearance of uncertainty. Clients pay extra for perceived determinism.
All this stuff about "what's best for the customer" tends to be an elaborate justification for complicated pricing schemes that alienate customers while ironically undercharging them for the services you provide.
Avoid customers for whom a week's worth of your time is a make- or- break- the- business decision.
thoughts?
That doesn't mean you work a fixed-price gig. It does mean that you give serious thought to a conservative estimate of the whole gig and then confidently offer that as your price for the engagement.
There's far too many things a potential client may not be telling you about the project, and it's incredibly hard for the independent freelancer to do enough business development, or for the client to do enough vetting, to know which random internet person is trustworthy. This is especially true when you're just starting out.
A one week sprint that solves a small, immediate need the client has will keep the project manageable, and protects both the freelancer and the client from a potentially bad situation. Worse case scenario, one of you is out a week's work. Best case scenario, after a few sprints a rapport and trust develops, and you can start providing your clients with estimates for larger pieces of work, knowing they'll be treated as estimates and not fixed bids.
Don't eliminate the appearance of uncertainty when you're legitimacy uncertain. That's bad communication. If a client needs solid estimates out of the gate they don't need an independent freelancer. They need a full-service agency.
Extra related point: some clients will really appreciate to have a higher quote that doesn't risk to go up afterwards, because the budget will be locked at project startup for internal reasons (vs. having a lower cost planned, but extra cost afterwards).