Tams/caps

Hello to all the new and old dreadies out there..wondering about my decision to get a tam or cap, not in any rush to obtain one as of yet cuz my hair is pretty short n no dreads yet but i did notice a comment from a fellow dread bout how after she started wearing a wool tam her hair started to lock up a lil faster..so my question is, is this true n what benefits are there from wearing one?