We started going yearly in 2010. At first, we would go between 5-8 days (using 5-7 day park tickets). My oldest was born in 2009, and the youngest in 2013. We would go 8 nights (Saturday to the next Sunday).
Right around 2016 or 2017, when kids were 7 and 3, we started going for 10 nights, then one time we went for 13 nights, and have not looked back since.
Our annual trip was oftentimes from October-February (to conserve our DVC points) and we would skip school, Last year, we shifted our vacation to June, when our oldest hit 7th grade because we decided school mattered now (we switched him to a very academically focused private school). Now we go after kids school year ends for two weeks. This upcoming trip starts June 15. Been planning since July. Can't wait!