A solid matter management system, and I include e-billing systems in that general category, should be able to tell you who changed what information and when. Such an “audit trail” is important if you need to see when a user modified a field – such as a billing rate field or a budget amount. . Audit trails help the legal department show that from a Sarbanes-Oxley perspective they have appropriate financial controls in place (See my post of Aug. 5, 2008: matter management systems with 35 references.).
Having acknowledged the benefits of audit trails, not every field needs to have such a tracking feature, only the important ones. The seed for this modest post was a reference in Met. Corp. Counsel, Vol. 17, May 2009 at 19. I suspect that having very many fields with audit trails adds considerably to system overhead and perhaps the speed of the system, so only important fields having to do with financial information should be candidates.