Only your department can answer this question. There is no set number of critical functions required. Some units may have three, others may have ten. It really depends upon your individual unit and what duties you feel must be "functional" or accessible during/immediately following an emergency to bring your office back to a somewhat "normal" state of activity. Try to group like items into one critical function if possible (for instance, you might have a broad critical function called “accounting functions” or “records management” into which you can provide a description of a wide range of duties). Remember, the more critical functions that you list, the more there are to maintain. Sometimes it just makes sense to group similar activities together and other times they are distinctly different and you may want to detail the plans separately. This is a unit specific decision.