When I was a practicing CFO, I once asked my controller to prove that his request for a new financial system could pay back within a couple of years. I thought I had killed the request. Imagine my surprise when he came back with a justification based on tax savings created by the system's more sophisticated fixed asset processing. Even boring replacement projects can be made exciting if the team is challenged appropriately. Stage the funding.
Most investments are a guess about the future.
By staggering the funding in multiple stages, you motivate people to continuously prove the concept to gain more funding. Invest in the front line. This is where your company interacts with its customers and channel partners, and where small changes can lead to big dollars, because you can influence thousands of transactions, decisions and behaviors. For example, in the restaurant business, investing in IT at the store level is the only game in town. If you can save labor hours, millions fall to the bottom line.