As per DCA principles, you must need to keep buying at dips with regular intervals as no one could determine the actual bottom. At the same time, you today buy a dip and tomorrow another dip happens then you do not need to buy again. You may go for buying dips at regular interval it can be weekly or fortnightly or monthly or anything which lead you to buy multiple times in a year (just based on your available funds but plan up for more frequency rather than being all-at-once).