I remember I was 12 when they started becoming frequent. Sometimes I sense I've done this before, and then BAM it hits me, or sometimes I realize whats going to happen next, as its unfolding... Mine are always in the form of dreams, that become reality... Sometimes something silly and insignificant, like a conversation, but I can recite the entire dialogue verbatim beforehand... Apparantly its common, so I dont take much notice.