It’s true. Researchers have confirmed it, dogs have no concept of scale. In other words, a small dog does not realize how small he or she is. Hence the well-known phenomena of small-dog syndrome. So why am I bringing this seemingly random factoid up?
Well, I’ve noticed a similar phenomena when working with web vendors. It can be hard for them to anticipate how long it will take to do work for you, especially if the work in question requires the creation of something that’s entirely new to them.
Now your developer by his or her basic nature wants to make a good product for you and please you because you’re the customer. That innate desire to please coupled with the difficulty of making accurate projections of time can mix together to make one, well, very expensive cocktail. They may tell you anything is possible, because, well almost anything is — for a price.