Historically, it’s been pretty hard to prove age discrimination in an employment lawsuit. That was primarily because it was up to the plaintiffs to prove the discrimination. Now, with a recent Supreme Court decision, that may change a bit.

On June 19, the Supreme Court ruled that employers will not have to bear the burden of proof. In other words, employers will no longer be able to just list the factors in a layoff decision — they have to convince a jury that age was not the motivation.

Because companies will have to marshal reams of facts when they defend themselves, legal experts say it’s important to maintain strict record-keeping practices and have a lot of documentation.