to drive 16K per year, you have 2 choices:
1) Start saving 25 cents per mile you expect to go over to pay the bill at the end or
2) Buyout the lease, which will eliminate all mileage penalties and excess wear. This can be risky because if you buyout a lease that you have gone far over miles on, it's book value will be less than the buyout amount, which will effect how a lender looks at the purchase. You may need to put money down when doing a loan on a lease buyout that you have far exceeded the miles you were allocated.