A:
Well, this answer is going to be my opinion. I have a macbook from early 2007 that still works perfectly fine. What the real question is here is how long will you be satisfied with this laptop.
Well, technology keeps on changing and we have another eight years to go at the very least. I would say that it will preform just as well in five years as it does today. However, there will be better iterations from now until then. Faster processors, better screens. There will also be better software made for it between now and then. There is really no telling.
I plan to use this laptop for about three years before I replace it. My macbook has been badly beaten and the battery stopped taking a full charge years ago.
Hope this helps.