My advice: ask prospective clients about budget, scope, and timeline. Your estimate should account for all of them and describe contingencies and their impact on the budget, scope, and timeline.

If you can, avoid working with people who balk at discussing budget, scope, timeline, and contingencies. It is at best a sign of inexperience.

But in the end, the three most important things are:

  1. Get the job.
  2. Get the job.
  3. Get the job.

Good luck.