I think the key is what you plan to use, and if you allow for the (inevitable IMO) expansion likely needed down the road.
Without getting into actual numbers, what we did was:
- Buy 1/2 as many points as we needed for our stay (X number of days, Y time of year, Z resort/room type), with the intent of going every other year - for our first home (CCV)
- Decided we wanted to go every year
- Buy 1/2 as many points as we needed for our stay at ANOTHER home resort, doing the same math as above - for our second home (DRR)
- Alternate every other year between first and second homes
- Add On again at VGF "just for a few nights each year", because we love it there .
IMO, it really is the best of all worlds. We book @ 11 months out at each home, we can also take "off the cuff" trips throughout the year. We didn't buy a zillion points to get started, we slowly added to keep up with our demand.