Buying tickets in advance

[eds]

Sorry if this has been asked before, But can you buy park tickets well in advance of your trip and use them 1, 2 or even 3 years later.

[Lola]

We're going to use two 5 day tickets we bought in advance last year (and then we had to cancel). Also we have a number of options left on old hopper tickets that we have been using up a bit at a time.