Client agrees to design. Mid development, changes everything.....

That's why you gotta lock that shit down in a waterfall contract

True. True.

That's happened to me recently, they sacked the designer after everything was signed off and 80% built. They hired a new director who elbowed in on the project and hired a new designer. I stood my ground and got paid for everything and requoted the job based on the new designs and how that impacted the work if already done. A complete pain in the a, but I'm not going to be out of pocket. I did have a basic contract in place. I started using https://www.hellobonsai.com/
For drafting contracts.

Cool thanks for the tip :)

That's why we have beautiful agile ways of working. It's not weird for people to change their ideas or expectations, it's just difficult to deal with that sometimes. But it's a fact of life and we do have frameworks like Scrum that can deal with that.