I remember once migrating from a system with periodic service contracts, where the old system set dates for all future contracted services at time of signing an

I remember once migrating from a system with periodic service contracts, where the old system set dates for all future contracted services at time of signing and the new one just calculated them as in start on X date then every 2 weeks. Ball ache. Having everything scripted so we could just keep running and tweaking and running and tweaking till it was right, then press go on the day was a good way to go. Of course the whole project was cancelled just before go live, but the migration worked like a charm.