Anytime Shani will play havoc. Why? Simple.
Shani is neecha in Mesha. But Mars the lord of Mesha is aucha in Makara (Shani house). It is common-sense for anybody to be treated with respect in somebody’s house, but Shani is not treated that way in Mesha. But Shani respected Mars in his house.
So whenever Shani becomes powerful (Ashtama Shani ) it inflicts pain to Mars (Mesha).
So it is just your karma. Find out who you disrespected and pay obedience to them. Given time (Shani need too much), Shani will test you and forgive you.