The one envelope at a time approach is called “single-piece flow - Eric Ries

launching a low-quality early prototype, charging customers from day one, and using low-volume revenue targets as a way to drive accountability.

Successful entrepreneurs do not give up at the first sign of trouble, nor do they persevere the plane right into the ground. Instead, they possess a unique combination of perseverance and flexibility.

Startups are different: too much budget is as harmful as too little — as countless dot-com failures can attest — and startups are extremely sensitive to midcourse budgetary changes.