People should stick with a program for a long time. Minimum 3 months. But preferably six months. They should get a solid taste of boredom. When the going gets tough the tough keeps going with the same training program.
I think people are way to creative and are too much seeking originality, entertainment and theory. Ross Ennamit once said wrote that Originality is overrated. That is so true.
I believe that suffering boredom for longer periods of time is a metric of a self control.
This is, of course, in line with the
Strongfirst WOD... And very much in line with how I approach training for the most part, sticking to plans for long periods of time.
However, I also think that one should feel free to add some spice to it within the principles. Same but different.
For example, following AXE with swings, but rotating the pressing movement every two weeks (alternating, say, low volume Bench Press with higher volume Military Press).
Personally, I have often played around with different (mostly easier!) rep schemes to keep things interesting and to emphasize the quality of practice. For example, doing 20x5 and 14,7 during my S&S period. Or, for example, today I did LCCJ weight ladders instead of my usual 20xCJC with the same weight. I still try to stay true to the program, but every now and then I like to try a "same but different" approach and introduce a heavier weight, or play around with a different technique, etc.
For some it might be as simple as adding some curls and triceps extensions, or having a nonstructured carry day.
That being said, keep the main thing the main thing.