Does your company estimate by one method, or many methods? There are more than seven different methods. How do you provide size and scope, as in T-Shirt sizing? Are the Estimates on target?
Fresh Eyes, Gap Analysis, Audit. Federal government agencies have the OIG providing recommendations. Click and your on your way to an OIG report. Skip to page 20 at the start of the recommendations. You cannot fix what is not known as broken.
Add up the time looking for something over a life time, the total will astound you. Someone is out sick and no one can backup that role. Time is ticking and money is wasting. Many of the techniques work for any business. Even if the company does not develop software or hardware.
Most companies review every 5 years. Technology changes faster than that. A plan is needed and the risks evaluated not only for company furnished laptops, tablets, and smartphones but "BYOD" Bring your own devices .
Inventory of Roles, Responsibilities, and Devices. Instead of measuring humans, measure the types of roles / function. Define the responsibilities, then account for the devices needed. Some companies have over 50,000 devices or more that should be in the inventory.