If there is one constant in the office, it is that everything will change. Once processes have been developed within a company, they need to be reviewed recurrently to ensure they are still effective, relevant, and up-to-date. A new member may have recently joined the team, or perhaps a new system has been implemented which alters the workflow in the office.
We have developed a system for keeping our processes updated at my company, Celaque. It includes periodic reviews, ad hoc modifications, and self-reviews. The best way to make sure the entire body of processes is always updated is through a programmed annual or semi-annual review. Self-review procedures and taking the opportunity to correct processes when mistakes are found are both essential practices to ensure that processes are in the best shape possible.