It very often is not done that way.
Yep. A major company I *used* to work for actually only maintained an FTE staff of about 20%. The remaining staff was all contractors, including a large offshore contingent. We got the job done, but I prefer the model I have now where the ratio is reversed. Offshore is used for the quick augmentation on a temporary capital build. If that capital build improves the business, you end up hiring more.
As I indicated to a different poster, this model has resulted in me more than doubling my FTE staff in the past two years alone. It works and allows us to take more risks with capital projects. We don’t worry as much about trying something out that may fail. We’ll try 4x as many projects - the ones that win end up having a huge ROI which allows me to eventually hire more FTEs. The ones that were a waste didn’t cost us an arm and a leg.
Simple, really.