Systems that actually run the shop
A system is what keeps the work consistent when you're not in the building.
Three layers
Tools (software, equipment), processes (how the tool gets used), and accountability (who owns the result). Owners obsess about the first one and ignore the other two.
Start with the constraint
Look at the workflow and find where things back up. That's your bottleneck. Building systems anywhere else first is moving deck chairs.
Don't over-tool
Most shops can run on three or four well-used tools. Adding a tenth one without using the first five fully is a tax on the team.
Take your version of this question further
This is one operator-tested angle on the question. Your shop, your size, your trade, and your team change the answer. Ask your specific version inside Ask a Shop Owner to get a response grounded in how owners like you actually handled it.