I am a 26 year old housewife and mother, and I've had numerous experiences of deja vous from as far back as I can remember. I have pondered over the hows and whys for years, but I was asked my thoughts on the subject the other day, and I was just as intrigued by my answer as my friend was(as I have a tendancy to answer questions without the need for the usual thought processes), I have never read, heard, or thought this theory before, and I believe I've had a type of revelation from my subconcious. So tell me what you think!
My answer to the question "what is deja vous?" was :
Well, I believe everyone has a kind of destiny, that we've all planned before incarnation in order to spiritually progress. Basically we've chosen our "destination", but we're making the route up as we go along(free will). Our higher self/consciousness(spirit) knows all, and has always got our true life path running in the back of it's mind(kinda like a pre-recorded video), no matter what we do, or how much we've veered off-course, which is why we sometimes make spontaneous, life-changing descisions, or get drawn to certain people and situations(our higher self pulling us back on course). Deja vous occurs when our life(thats a bit off-course), gets back on course. At the moment of deja vous, life and fate touch, so we experience both at the same time momentarily, thats when we say "woa, deja vous", and we start thinking, which in turn usually makes our waking mind take over, and our link to our higher self is disconnected(which is why most deja vous only lasts seconds-until realisation!). I believe having a deja vous experience means I am on the right track to fullfill my destiny, and I usually find them quite reassuring, especially just after making a big descision, as then I feel I'm doing the right thing.

I then went on to say: it's as if you are walking along the kerb, or a low wall, sometimes one of your feet slip off, but the other one stays on the kerb(imagine the foot on the wall is your fate, and the foot thats slipped is the life you're living). When you bring your other foot back onto the kerb, you momentarily look down to check your footing, thats when you see your two feet, which fleetingly look more or less the same(aka. deja vu), then you look up again to wherever your headed.
My deja vous experiences vary in frequency, duration and intensities, but all aspects are noticeably more if I'm at a major turning point in my life.