In California there are a variety of reasons why a SR 22 may be required and the length of time one is required to maintain this financial responsibility certificate may vary as well. 

For example when your license is suspended under the CA Financial Responsibility Law because of an uninsured accident you can request a non-commercial restricted license. As one of the requirements to obtain this license is to file a CA Insurance Proof Certificate (SR-22) and keep it on file for a total of 4 years from the suspension effective date according to CA DMV.

For other reinstatements of your license after a suspension or revocation you must maintain the SR22 for only 3 years. So if you are required to hold a SR22 in California contact the CA Department of Motor Vehicles to find out how many years you are required need to maintain it.