Even if you only go once a year, you can time your trips to use an Annual Pass for two trips.
For many years I would visit WDW for a week every December. On the first trip, I would go the 2nd week in December and buy an Annual Pass. Then the second year I would go the first week of December. Because the AP expires 1 year from purchase, it was still good through my second trip, usually expiring the day we left for home, or the day after.
This alone usually saves money on the price of admission across the two trips. (It just requires a bigger outlay of money for the first trip) Two 7-day base tickets are within about $10 of a new AP. If you wanted to add Park Hopping to those 7-day tickets, they're now more expensive than an AP.
And all that is even before you start factoring in the shopping discounts and possible room discounts.
Then there's the ability to buy the Tables in Wonderland dining discount card...
-Rob