We aren't
DVC members.. yet.. but we are in the process of trying to purchase resale points, and I can share my thoughts on what made me pull the trigger.
I looked at it three ways:
1. Past history
We have gone down 7 out of the last 8 years anywhere from 4 to 9 nights. Between my wife and 2 kids, we would get a single room in a moderate or deluxe resort, so our average lodging cost was around ~$3k.
So, for the past 7 years, I paid about $21k in lodging.
If I bought $15k of points (~160 depending on resort) and paid about $800 in annual fees for 7 years, I would have paid about $20.6k for lodging as a DVC member. So, I figured that around the 7 or 8 year mark I would hit the break even point. After that, the annual fees would be cheaper than paying cash at a resort.
2. Some Internet Spreadsheet
I found an Excel spreadsheet on some board and updated it with 2012 numbers. At this point, I was looking at 300 points at SSR. If I recall correctly, the "cost of owning DVC" came out to around $20k in initial buy-out (no financing), $50k in annual fees for the points for 40 some years, and about $19k in lost income (i.e. investing the $20k at a 6% return and paying for your vacation lodging with interest profits and re-investments). So, all in all, over 40 years, I would be out around $90k. Assumed a 3% annual fee increase a year.
Instead, if I stayed at SSR for 40-some years assuming some (likely conservative) growth ... maybe 5%? I think I would be out something like $160k for lodging.
So, in an apples-to-apples comparison of where you stay, you would save money.
3. The ability to share
We go down with my wife's parents and my sisters and sometimes friends just about every year. If we had people stay with us, either in a 2br, or in 2 suites, we would simply ask them to pay the annual fees for us. It is cheaper for them than buying lodging with cash, and they are happy to do so. If our points come through this year, my wife's parents would cover annual dues and my sister would pay for the kid's park hoppers.
Doing that consistently would let some friends stay with us for as little as $400/wk for lodging. For some, that's the difference between a trip to Disney for their kids, and not. And it is cheaper than them renting points.
Of course, we don't count on it, and it's not as if we wouldn't let family use points if they needed to for free, but this seems to work out for everyone involved.
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Whew, that was a little long.
Some assumptions that we had are that we will be going every year, and staying, on average, for 7 nights (right now we are looking at 9 nights at the end of the year for 2012).
We also assume that the family suites in the value resorts (like art of animation which looks awesome) cost in the moderate-resort range ($260ish a night?).
We figure we will break even anywhere from 5-9 years depending on how often we go and who "comes with". I'm confident with the age of our kids that we will recoup the investment in the short term. Once that happens, I'm happy with the purchase because even if we reduce our travel frequency, we would give points to family or rent them to offset the annual fees from that point onward.
I haven't fully researched two important options:
1. More savvy financial management of an initial lump-sum investment to cover vacations out of interest. My fear there is that it may take a lot of oversite and knowledge, and near-term market fluctuations may have a big impact on vacation plans.
2. Simply renting points from DVC members. If you can always get lodging for less than the cost of annual fees, it seems to make sense to not be a member.
Both cases trade savings versus determinism, and it's not clear that the "emotional cost" of yearly fluctuations offset the finances significantly to make me want to abandon the "warm fuzzy" I like to have around my vacations.
Hope this helps, and by all means, I don't claim this is bullet proof, but it was the rationalization behind our decision.
-Ed