Started when I was 13yo, and they've always been like clockwork. I've always known exactly when to expect it (as in, the actual time of day). I also know for how long/many days it'll last.
That never changed after I got the pill. Now I'm just lucky enough to be able to skip it a month if I'm travelling or something, and don't want the experience ruined by it.
Also: I hardly experience period cramps, and don't bleed a lot either.