Maximum number of routines

What is the maximum number of routines that can be assembled in the flow panel?
Is there even a maximum number or is it unlimited?

If you are asking this question, it is very likely that you are doing something wrong.

Even relatively sophisticated experiments likely have only a few types of routines, and maximise the use of loops and maybe some code snippets to get maximum flexibility and re-use out of them.

Large scale duplication is a likely warning that you need to re-conceptualise the way things are being implemented. So a better question would be “Here is a detailed explanation of my design and procedures. Here is a description of how I am currently attempting to implement it in PsychoPy (with screenshots). It looks like it is getting out of hand. Can anyone recommend a more efficient way of implementing my design?”

I don’t have a specific experiment in mind, I understand that it is most efficient to re-use trials and make use of loops etc. but I was wondering on a more theoretical level whether there was a limit to how many routines you could create in a flow panel.

No, there is no fixed limit.

But practically, large numbers are strongly indicative of a non-optimal implementation.