Written contracts are only worth what they cost to defend.

(I’m a cynic but a happy one).

The projects least likely to have the plug pulled (in my experience) are regulatory ones where the industry regulator is breathing down the neck of the company to abide by a compliance issue.

Learn the business/industry as much as you can. I believe I’ve gained more credibility with business representatives from a capacity to talk business issues in their language than any technical knowledge (ever mention an ER diagram and have a business person think you meant a medical program on television?).