What’s the thing that adds value to your customer? What is the part they’re actually paying for?

How much of your time is spent on that thing/those things?

How much is spent on other things and how can you reduce that, especially for any resources that are your constrained (rate-limiting) resources?

It doesn't have to be a factory producing physical goods. Anytime we have a multi-stage process with different team members responsible for various stages with interdependencies, you will find constraints abound.

ToC tells you that while there will be multiple constraints, your biggest bang for the buck comes from identifying the limiting constraint first and finding workarounds to break / relax that. Focusing on the non-limiting constraint would not give you the best benefit.

This is such a general concept that we can apply it to so many processes whether it is sales, customer service, bug triaging/resolution, logistics etc., Any place we observe a queue (whether visible or hidden), I can guarantee that there is a lurking constraint somewhere.

The Phoenix Project is based on The Goal but applied to the software industry.

If your specialist employees are spending their time doing non-specialist work, then perhaps you have not set them up to work efficiently.

Yeah, that's what it's for. But the ideas generalise to general project-management and processing of 'stuff'. A lot of it makes sense in multi-person hardware development projects.