[Cory]

The answer is it depends.

If you have something that needs to be extremely accurate, or you need to make a bunch of them, or it has angles and contours, then you'd want to use the CNC.

If you have a simple part you can make with a bandsaw and a power drill, you wouldn't want to use the CNC.

My formula for buying COTS vs making your own would be to decide:

Can we get the same functionality out of a COTS part as a custom?
How much more will it cost to go COTS?
How much longer (or shorter) will it take to get the COTS part?
Am I going to spend more than price premium of the COTS part to actually make it myself?
What else could I be making with my CNC, that isn't available as a COTS part?

If the answers to those questions favor COTS parts, then it's probably a worthwhile investment.