Sprinkle switching circuits liberally with small capacitors?
In my experience, bypass caps are required next to modules that can switch state,(flip-flops, memory, etc.). If you don't do it, your circuit very likely will experience erratic behavior, and even failure.  This is a lesson I learned on my own when my designs were working erratically and were highly susceptible to electrical noise.  After that, I paid more attention to, and followed the recommendations of the module designers.
  Then there is the matter of the project schedule.  Usually they want the circuit/design working "yesterday." So, you have to decide, do you want to spend time determining where you need bypass caps or making/improving your design?  If you take the recommendations of others, then you don't have to spend time on that.
If you work for a large company, other people will verify and test your design - which is good. If not, then you will have to do it all yourself, leaving the user exposed to any mistakes you might have made.  An example of this, that comes to mind, is the Hover-board. There is a major design flaw with it, which was not caught (or ignored), before releasing the design to production.
So, yes, learning from the mistakes and experience of others, is part of becoming a better designer yourself.