I would guess, since it’s suggested to get a booster six months after your second shot, that after roughly six months it starts to wane. At least that is what I’ve read and what dr”a and the CDC say.Hows the vaccine and booster compare? We don't know because from what I understand the CDC isn't doing any statistics on natural immunity from prior infection.
Almost everyone I know that has had the vaccine including us has since contracted covid. DW's boss just got it and he just two months ago was boosted. It's been many months of the covid positive #s being 23% to close to 50% coming from vaxxed, week after week avg positives have been on avg 24% vaxxed.