Another thing to remember is that you are buying a long-term product. Right now, you're ability to vacation is limited to certain times of the year. Remember, the DVC will be yours until 2042(if you buy OKW,VWL,BWV,BCV).It will be 12 years longer if you buy at SSR. My point being, what you are able to do now may be very different than what you will be able to do 15 or 20 years from now. Your family structure may be very different...think about being empty-nesters going with friends as opposed to family(WDW as an adult is VERY different than WDW with kids!!!!!!), think about possibly taking grandchildren someday etc.
Right now, if you can go every other year, during the summer or during school vacation weeks...well, OK, it's not ideal, but one of the benefits of the DVC is that it breaks that "commando tour" habit that people get into at WDW. You know...."I'm here, I may not get here again for a long time, I've got to see everything". With the DVC, you KNOW you will be back. So, if you're there in August, schlepping around the MK, and you're hot, tired, and cranky, go back to your hotel, swim in the lovely pool,rent a boat,relax on your deck, relax by the pool, catch some sun and jump into the pool every few minutes to cool off, shop in some nice air-conditioned stores, have a lovely meal somewhere...you get the idea. You'll be less apt to think you have to slog through the boiling hot, crowded park if you know that within the next year or so, you'll be able to come back. DH and I were there in July, and that's exactly what we did. We went to the parks, when they got to be "too much", we went to the hotel and swam, went to DD and shopped, went to some of the offsite outlets and shopped, went out for lunch, went and looked around WWS, went and walked around Celebration, hotel-hopped(one of my favorite things to do...going to take a look at the different hotels on property).
DH and I are in our 40's, we have no children, and we go to WDW at least once a year, and sometimes more. The DVC has made a world of difference in our vacation style, it's nice to have a fridge in the room for snacks/drinks, it's nice to have a washer/dryer so packing is easier. It spoils you.