CALEA is not a time machine. When an order is received, the "collection agency" starts receiving traffic; nothing (or at most, very little) is known prior to the wiretap order. Put another way, you cannot be ordered to produce tapes of phone call that happened a month ago. (CALEA only says you must have the ability to monitor anyone; not that you must be monitoring everyone to have "stuff" available before being asked for it.)
Another point about CALEA is that you don't *have* to have infrastructure in place in advance of the order. You simply have to provide Law Enforcement the wiretaps they are asking for -- however you accomplish it. You don't need to solve for every case, just the case they ask of you at the time. This keeps the cost of compliance way down (provided you don't need these for a significant percentage of your user base). Between e-discovery and RIAA issues, retention times are probably shrinking even though capacity for retention is growing. Deepak Jain AiNET