I would guess it’s roughly linear. Should be good enough as an approximation. So if smoking daily is, say, -8 years life expectancy then smoking weekly is proba

I would guess it’s roughly linear. Should be good enough as an approximation. So if smoking daily is, say, -8 years life expectancy then smoking weekly is probably around -1 year. Once it’s very infrequent like once a month it’s probably negligible.