For those making physical products, where do you get your designs?

I’ve been thinking about how much time small creative businesses spend on the actual design side of making products.

If you’re making things with a laser cutter, CNC, or other equipment, do you usually:

create all your designs yourself?
buy individual design files when you need them?
use a subscription/library for access to lots of designs?
or mostly work from your own templates?

I’m especially curious about people who actually sell what they make, rather than just making projects as a hobby.

At what point does paying for ready-made designs become worthwhile compared with spending the time designing everything yourself?