DE and SE dreads and braids are usable for 1,5-2 months. Basically, it depends on how fast your natural hair growth. The dreads are unbraided painlessly and can be used more than one time.
While wearing dreadlocks and braids, hair will fall out of your head every day (as on ordinary days without dreadlocks and braids), but all this hair remains on your head due to the fact that they are braided. After removing the dreadlocks and braids, all this hair will be combed out.