In Nevada proof of insurance through an SR-22 can be required for different amounts of time depending upon the reason that you are mandated to obtain this financial responsibility certificate.
If you are required to get an SR-22 due to being in an accident while operating a vehicle that did not have insurance, the Nevada Department of Vehicles lists that you must carry that SR-22 coverage for 3 years.
The suspension and revocation section of the Nevada DMV goes on to discuss the SR-22 proof of financial responsibility. If you are required to file an SR-22 form to reinstate a license that was suspended or revoked due to a DUI or other offenses, the period of required coverage begins when you actually reinstate your license, regardless of when this occurs.
The NV DMV goes on to state that there is no time limit or statute of limitation on SR-22 insurance requirements. The DMV does not notify drivers when the period of required coverage ends, to find out when your SR-22 coverage can be ended, contact the Nevada DMV directly.
If you do not maintain SR-22 coverage continuously during your required time period, your insurance company will notify the DMV. Upon notification the DMV will suspend your license and inform you of this by certified mail. To have your license reinstated you will need to again obtain SR-22 coverage and the required period of coverage will start over.