Board Thread:Questions and Answers/@comment-32856983-20180315152656/@comment-31529160-20180317063922

They are everlasting. If you can remember the exact fighter(s) you applied it on then check again and you'll notice it should still be active ( Their ratings will appear blue-ish as well). Remember it only affects your fighter's stats when challenged and not when you're playing as the fighter in H2H.

TJ Grant above was one of the early fighters I applied a Defensive Perk on back in S12 (BJJ Season) and as you can see the blue colored rating is a sign that it's still active