Flexible and is mutually discussed/agreed. But we prefer the Work Milestones payment terms, I mean, Pay as you go and see the progress.
20-25% upfront payment
20-25% Design Approval, and after first demo on our Test Server.
20-25% after completing and launching the BETA version of the final project on out Test Server.
20 -25% after implementation on live domain, acceptance testing by client and bug removal.