>Depreciating means that if you pay an engineer $200k in a year, in tax-world you only had $40k of real expense that year, even though you paid them $200k.
what happens if an engineer leaves after the first year, or at any other time?
what happens to the calculations then?
Nothing. The calculation has nothing to do with people. It’s about what the company spends - and some kind of spending is capitalized depending on what activity it was related to and what the output was. That doesn’t change if the employee that you paid a salary to leaves, or the company that you bought materials from disappears, etc.