We first bought when the kids were very little. 300 points got us where we wanted to be since we were able to travel in the off months. Our preschool had a modified traditional school schedule and gave us 2 weeks off 3 times during the year. This was amazing, we could travel at value times and avoid the crowds. Then our next school had ski week, another bonus!
Sadly, high school puts us in a bind. There is only one true week during the summer that we can travel, right in the middle of everyone else and right in the middle of the high season. So, we ended up buying 300 more points at another resort so that we can travel when we must. Eventually, this will probably be too many points for a retired couple to use, however, we are hoping that there are grand kids...
There are restrictions to combining points and using points from canceled plans. Now, we try to figure out every two years to go on a great trip using current and banked points.
For cruises we get 2 rooms since the kids are too big for all 4 of us to be comfortable together. We love to spread out in the timeshares and prefer a 2 bedroom; however, we have squeezed into a studio or even a 1 bedroom when they were small.
Basically, it seems that our points needs grew over the years so 600 points total suits us well now (personaly, I would like more, but DH says no) which only allows us to go every other year. I supplement with cash when we need to.
Our next venture hopefully will be Europe or back to Maui at the Grand Wailea, one of our other memberships. My advice is try to get a hold of a point book which shows when and where you can go for how many points. Points seem to be going up for rentals over the years (owners since 1996). Also, new things are added like Adventures by Disney, which require a lot of points. Some we will never go on with all points because we don't have enough to cover the costs.
I remember they wanted to sell us the 100 point package at first and I'm glad we bought more, since the price has gone up tremendously since then. Occasionally, after you are a member they will roll back the prices and offer incentives, but when i think of what those first
DVC members paid, I am envious. We debated for years before we jumped in.
Good luck and think about what you will use and how you will use your points in the future.