We're really glad we bought in at the minimum we thought we'd use because it allowed us to use
DVC for a year and learn the answers to some important questions:
1. How many points did I actually need/want?
2. Could we really afford all the non-lodging expenses of multiple Disney trips each year? We were used to paying for all-inclusive MYW-type packages. (For us - the extras run about 1,000 - 2,000 per trip

and that is not including 1,500 for APs)
3. Which resorts did I want to stay in? Which resorts did I not want to stay in?
4. What type of room did I prefer? (For us - paying extra points for premium views is absolutely important).
For us, I could not have answered any of those questions accurately pre-ownership. After one year, we decided that:
1. We needed 50-100 points more if we were going to vacation the way we wanted to (i.e not be tied to low point resorts/views).
2. By budgeting and planning ahead, we are able to vacation more frequently than we did previously. This does come with a cost. I do spend more on vacations now than I did before - DVC has not "saved" me money in the sense that I spend less - but I do get more for what I spend.
That said - if I decided to use my points for a week-10 days in 2-bedrooms, I would probably spend about the same as I used to on food/tickets/etc. Instead, we do studios and this year - we'll spend 24 nights in DVC lodging.
3. and 4. I thought going into it that "as long as we're at Disney, who cares what the room is like". I've found that I am not really crazy about the value views/rooms. For the lowest amount of points, I can stay in a value AKV studio, standard BWV studio, or OKW studio - and those would be my three least favorite places to stay.
The great thing is that adding on via. Disney is REALLY easy, there are usually great incentives, and you can add on in small increments to get the right amount of points.
For us, AKV was not on the table when we bought in. A year later, we added on at AKV

.