[toast42]

As a follow-up to this question, imagine a job where a significant portion of time is spent waiting on a computer (rendering animations, code compiling, etc).

Two contractors are hired, one with a modern laptop and the other with a 10 year old machine. The older machine takes at least twice as long to process the work.

Is it A) ethical to bill for time spent waiting for the machine to process and B) ethical to use the older machine? Assume the contractor using the older machine is using the best equipment currently available to them.