slow time - just that is non busy times right.
WDW
DVC resorts - later Aug, Sept, May - use to be Jan but the demand for it went up.
busy times - Dec 1-14, thanksgiving, food/wine festavial, christmas to ny, sometimes during spring break some weeks you can get even last minute (2 months before) others you can't get even 7 months before. hard to tell before which week it will be - depends on the different school & college breaks.
non-WDW dvc resorts - don't have the necessary experience.
know that HH is about impossible to get in the summer
VB is impossible to get during spring break and christmas