The way these projects are managed has changed in the last 10 or so years. In days of yore a proposal would be based upon a client’s brief, developed, tested and signed off. Once the brief is agreed, that is what is quoted for. Big projects with a big price tag. Modification and testing costs may be included, or billed separately. A couple of small modifications are sometimes included, more often quoted as ‘extras’. As are client caused delays. Many would have support packages to extend the project as it grew and developed, eliminating the problem with change orders.
This puts a large burden on all involved, developers work under financial pressure whilst the client has to keep up with unfamiliar technology and takes a hard financial hit at the end.
Assuming all goes well. And the original brief was correct and complete
Staging development and payments can help, though not always the answer. Projects can fail for many reasons, expectations not being met, or clients running out of passion or money. Entire agencies have gone out of business before completion whilst the client chases funding. This works for no-one.
The road to hell is paved with good intentions etc. ..
Learn more about building a website
[article part of Supporting You > Building Your Site]
