The effective date for your increased benefits will usually be the date VA receives your claim for an increase or a new disability.
VA may award an earlier effective date for an individual evaluation of a current service-connected disability if private medical evidence reveals that there is an increase in the veteran's disability and a claim is received within one year of the factually ascertainable increase.
For example, if there is medical evidence to show that the veteran's service-connected left knee arthritis was worse on June 13, 2009, and we receive a claim for an increased evaluation for the veteran's left knee arthritis on December 6, 2009, then the effective date for the increased evaluation will be June 13, 2009.
Additionally, VA will also consider treatment reports from VA or the uniform services, and the date of admission (or examination) will be accepted as the date of claim (unlimited retroactive entitlement) when increased disability is shown.
For all current information about compensation and pension, eligibility, payment rates, applications, etc., go to http://www.vba.va.gov/VBA/