Hi Jane, each case needs to be judged on it's own merits, but a reasonable rule of thumb is , would you visit Disney once every two years. If the answer to that question is a yes, then IMHO DVC needs further investigation. Here are a few more questions you need to look at
Do you prefer to stay on site ?
Would you still take holidays to Disney without children ( when they are grown)
Are you prepared/able to commit a pretty hefty amount to pay for future vacations? ( because the difference in having the money available and whatever your loan rate is will make a big difference to the cost effectiveness of this option)
Is staying in accommodation of a better than average quality important to you?
If you make yes to all those as well then you're really on your way.
I would be vary wary of advising Brits to use DVC as their only accommodation option as , IMHO, it's a pretty expensive one unless you're pretty sparing with it. If you're looking to use DVC points for a three week stay on a regular basis, thats A LOT of cash to come up with, BUT to use it as a "high light" for a holiday it does, IMHO really finish a holiday off in stlye. While I'm sure other people have other ideas that work for them, I found that 2 DVC stays of 5 days each for a 3 week holiday is just the right amount of luxury, without breaking the bank and still allowing me enough time off site to take in all the things there are to do in the rest of Orlando.
Please feel free to ask away with your questions as I'm sure you'll get plenty of help/advice on how to make it work best for you.