2-3 times a year (I'm up to 40-something lifetime trips). Once in January, once in August, and sometimes in June for a few days if we've taken our beach vacation in SC. We're DVC members, and my dad has the system down to a science. We've also been to DL twice, and my dad bought into Aulani so we can go there every few years
. We just save and save wherever we can. Being DVC members and AP holders really helps. Tables in Wonderland offers a 20% discount on TS meals, and then the AP discount on merchandise helps a lot too. We probably spend about a month out of the year in WDW.
My graduation present for HS was a girls' trip to WDW. I couldn't go with my parents in January because my semester started early (with all of the snow we got, they learned their lesson and are starting at the end of January this year). So my dad paid for me to go to WDW. He footed the hotel room (Pop on an AP discount), gave me a spending budget for food and souvenirs, and he paid airfare (though between frequent flyer miles and some vouchers we had because Southwest misplaced our luggage, I think it came out to $22.
) My best friend came with me and we had such a blast.
For the record, my dad is awesome.