Most of the time I will make a photocopy of the spread/reading, along with notes to add to my journal. It is interesting to go back and see the issue from a different perspective.
I agree with the notion of reading for a given question once, or maybe even twice for clarification, if necessary. To keep asking the same question without contemplating and considering the answer already given is like asking for advice/guidance, and then not listening.
People have asked me this question- "how can those cards be accurate if it is posssible for me to go see another card reader later today, or tomorrow, and a whole different set of cards can be drawn"?
My answer to that is the importance of one's 'genuine intention'. To get the most out of a tarot reading, in my opinion, the querant would do well to consider the information gained as something like guidance/advice from someone who has the querant's best interests at heart. The information gleaned is to be considered and some thought on behalf of the querant as to how to move forward relative to the issue at hand would be most useful.
While I practice with hypothetical questions posed, creating spreads, etc., it never seems to be quite as interesting or as satisfying as a real question from a real person.
Thanks for posting the question- it is one I get asked quite a bit, actually.