We got at least once a year, depends on who is going (just DH and I vs us plus the 2 kids) and when as to what we spend. We usually look at our budget and then decide accomidations, etc. Our last trip wa 6 days for around $1600 that includes getting upgrades to AP's BUT we drove this trip (we were doing it on a tight budget). Of course when we have AP's we go more, this year will probably be 4 times before they expire. Twice more alone and one family vacation w/ the kids.
We also do other famliy vacations (if it were my choice it would be all Disney all the time). We always do one other plus Disney. Last year was Seattle and Daytona, the year before Myrtle Beach. This year was an exceptionally busy year: We got married, honeymooned in Texas (San Antonio, Austin, and Houston), went on a mission trip to NYC, spent a week in Williamsburg, VA and then went to Disney. We also usually hit a nascar race or two for a long weekend.