Since VA benefits are retroactive, how far do they go back?
This question is about the "Effective Date" of the claim, and there are hundreds of rules and exceptions to those rules that cover this topic, but let's talk about the three most common.
For the vast majority of cases, the general rule is that the Effective Date will be either 1) the date you filed the claim or 2) the date entitlement arose WHICHEVER IS LATER. This means that for most people, the date the claim was filed will be the date the VA uses to calculate the backpay.
If you file your VA disability claim within one year of separating from service, the Effective Date will be the date you left the military.
The rule that confuses most people has to do with cases that were denied, closed and then re-opened. Once a claim is decided, a Veteran has one full year to appeal the VA's decision. If no appeal is filed, the claim is closed. A claim can be re-opened using new evidence that 1) the VA hasn't seen before, and 2) would have helped to come to a favorable decision the first time. If successful, the Effective Date for re-opened claims is the date of the NEW claim, not the original one.