1. A method for finding an optimal preventive maintenance/replacement schedule for a set of assets comprising: receiving, at a programmed processor device, data regarding an asset, said data including a failure rate function of said asset, a cost of preventative maintenance (PM) of said asset, a cost of an asset failure, and a cost of replacing an asset; computing, using the programmed processor device, an optimal number of preventative maintenance actions K and time intervals t k for each asset independently by minimizing a mean cost-rate value function with respect to an age of the electrical asset y k , wherein said schedule is formed without considering a labor and budget resource constraint; and storing said optimal number of preventative maintenance time intervals for each asset as data in a memory storage device; and generating a schedule of said optimal number of time intervals from said stored data.