On the other hand, you can easily drop $5k in one sitting without it being a big repair item (my new injectors comes to mind). It all comes down to how many miles you run, how well you maintain your truck, a good mechanic to look your truck over every time you come back in for any defects getting ready to happen, and a healthy dose of luck.
We started out setting $.10/mile aside for repairs, and so far this has worked well.
Vernon in C2197