My first suggestion -- as others have said -- is to lose the concept of "investment."
A timeshare is NOT an investment -- and that's not a knock on DVC. NObody's timeshare is an investment. Depending on what you buy and how much you pay (both acquisition cost and annually), a timeshare may be a reasonable vacation option. Or not.
The second suggestion I have is to make first decisions first.
FIRST...decide if you want to get involved in ANY timeshare. Most timeshares involve a never-ending financial committment to significant annual payments (usually called maintenance fees, called "dues" by DVC). DVC's "dues" are a committment for 30-50 years, depending on what resort you buy. That's longer than the mortgage on your house, and although the numbers are smaller, it is still a very significant longterm committment.
No, you don't have to keep any timeshare forever and ever, Amen. But...if you're not going to keep it forever, you need to have a realistic exit strategy. If you pay THOUSANDS of dollars to buy in, a rational exit strategy becomes very problematic. If you pay those kinds of bucks and get out later, you're going to take a financial beating.
In making this critical first decision, you need to consider ALL options to timeshares. That includes traditional cash hotel reservations (often with good discounts), renting reservations from timeshare owners (including DVC owners), staying offsite at WDW with really significant savings, and buying other timeshares instead of/in addition to DVC.
My third suggestion is -- before you buy DVC -- REALLY consider how you plan to use it.
IMHO, DVC is a fine timeshare...IF you use it exclusively for DVC resorts at WDW, and if you just wouldn't be satisfied staying anywhere but onsite in "deluxe" accommodations (and some would dispute that description of DVC).
I would argue that there are better options everywhere else where DVC has resorts. Better in Hilton Head, better on both Florida coasts, better in California, and WAY better in Hawaii.
Using DVC points outside DVC is a sucker bet, with a few exceptions in RCI trades.
Fourth suggestion -- speaking of RCI: If you want to do any exchanges other than when you've screwed up and have expiring points you HAVE to deposit in RCI...buy something else.
With regard to RCI, you have to understand what DVC is...and isn't. With many timeshares, you receive a full personal membership in one (or more) of the major timeshare exchange programs -- RCI and/or II.
That's not true with DVC. With DVC, you are not a member of any exchange program. You can exchange through RCI currently, but only a very limited number of choices (<600 of the more than 4,000 RCI resorts) and only through DVC MS.
IF you wanted to buy a timeshare for the purpose of exchanging (not recommended), you could buy a fine timeshare on eBay for $1 and get access to all 4000+ RCI resorts, plus all of their other significant benefits.
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So take your time. Take a deep breath, and do your homework. Don't try to force a fit. You'll be sorry if you do.
And...as a Dad to three beautiful daughters (2 adults and a 10 y/o) I can tell you that there are SO many things that are so much more important than trips to Disney...or anywhere else.