Strangely enough, Ash Wednesday is not a holy day of obligation for Catholics. Even fifty years ago (as far as I can tell), when observation by Mass attendance was near-universal, it wasn’t required although it was strongly urged. Nowadays it seems bearing the Sign as a dark smudge on your forehead sets you apart not just as a Catholic but as that most exotic of birds, a traditionalist (or “trad”) Catholic.
Well, not really, since even Vice-President Joe Biden, held to be a “cafeteria Catholic” because of his pro-choice voting record, sported a thumbprint-like mark on TV this week. And observance isn’t strictly limited to Catholics, though it isn’t common at all among free-church Protestants. But it’s safe to say that Ash Wednesday observance is notably absent to those who have any memory predating the death of Paul VI.