Margins. Does it increase or decrease your margins?

If we are talking about something like a fastener; if I’m doing 10, I’m probably not going to notice if it saves me time. If I’m doing 100 I would probably go more expensive but probably bitch about it. If I’m doing 1,000 I’m going faster every time because I’m going to lose those hours somewhere else in the project when something goes wrong.

OP, what’s your field?

Time is indeed money. If you can make the same amount of money per job by shifting your parts to labour ratio towards parts then you will be able to sell proportionally more products/services because you can get through each job faster. However, what are the parts in question? Are they easy to store or are they big and heavy? Are they easy to source allowing a ‘just in time’ supply chain or do you need to maintain a stick in order to facilitate the rapid turn over of jobs you can do by reducing your spent labour time on each job? Are parts of consistent quality?

Most of this is relative to your industry. I’m guessing motor/engineering? Maybe HVAC?

generally yeah because it’s cheaper to scale up and critically scale down material purchase to reflect demand than to hire or fire staff.

The answer depends on how much unit variable cost changes in relation to the change in operating expense.

Solving this requires sales (price X volume), truly variable cost (excludes labor), and operating expense.