I met my wife through friends, not through massive amounts of dating. After first date with the woman that ended up as my wife, I mentally gave it two months. Some where along the way it got out of hand and we have been together for 28 years. Who would have known.
Personally I do not believe immediate attraction is more then lust and lust is not a long term thing. You have to get to know people and that takes time. If you know someone and can accept them for who they are your likely to love them. Then there is the question whether you can stand them, do you trust them, are your lives compatible. If your lucky the lust part comes and goes and comes back again over the years but it is not the basis of our relationship.