Also there is (yet another) a problem with insisting on experience, which is that a supposed experience of ghosts/spirits only counts as one if you choose to interpret it that way. I have, like everyone, had experiences which I, personally, cannot explain - either because I wasn't paying enough attention at the time, did not feel inclined to investigate further for whatever reason, or that I simply wasn't sufficiently equipped/educated to explain. Whether I choose to immediately smack the "ghost/supernatural/spirit" button to explain whatever happened is a completely different question - and it's one that you're far more likely to smack if you're already somewhat believing. Personally, I don't think my own inadequacy/ignorance when it comes to explaining unusual things is proof that they have a paranormal/supernatural explanation.
So, "you have to experience it to believe it" essentially just means "you have to believe it to believe it." It's meaningless.