The 70% maintenance cost is a little misleading. It is better represented as the total cost of owning a software system. For any large software deployment, 70% or more of the total cost of the software is represented by maintenance costs. Think of it like buying a car. Once you have the car, in order to keep it running, you still need to put in fuel, buy new tires, etc. Over years or even decades the cost to maintain your car approaches or surpasses the initial cost to purchase it. For example, if you spend $50 per week on gas, over a decade you are approaching a 50/50 split based only on fuel costs ($26,000). Buying a completely new car might marginally improve your weekly outlay if -- and its a big if -- the car is more fuel efficient. Still, buying the new car means you're now putting gas (or hydrogen, or electricity) in a different car, not that you've removed the need for fuel. You can change the model by buying a new care every year, but that just adds to the acquisition cost, it doesn't really lower the maintenance costs. Software is the same. Replace it when the frame rusts, or the engine falls out, or there is a significantly better technology available; not because you're spending money on gas.