Non-delusion is a condition of longevity, because one who is undeluded will know what is beneficial and what is harmful, and by avoiding the harmful and resorting to the beneficial one will have a long life.~Nyanaponika Thera(I don't know if he's quoting the Suttas or not)

Tibetan long life Amigayus practice: http://www.tsemrinpoche.com/tsem-tulku-rinpoche/buddhas-dharma/amitayus-sadhana-practice.html

Nyanaponika Thera said (I don't know if he's quoting the Suttas or not),

Non-delusion is a condition of longevity, because one who is undeluded will know what is beneficial and what is harmful, and by avoiding the harmful and resorting to the beneficial one will have a long life.

See also this Transcript: Amitayus Sadhana practice (which is Tibetan long life practice).