Itās very subjective, and very contextual.
We sense patterns in non-repeating material, because some of it does repeat.
Put another way, we sense patterns in non-looping material, because itās mathematically impossible to eliminate repetition.
(Any aspect of your music could create a memorable hook for some listener, and theyāll notice its coincidental return.)
I guess the question is what your goal is, compositionally.
If you want to disorient the listener but still keep track of your own place in the music, I think you might be looking at this backwards. Youāre not looking for where the limits are, because you getting lost as a performer defeats the purpose. Instead, youāre looking for subtle queues to latch onto, that the listener might not know to listen for.
(And yes, the listener will probably latch onto those queues as well, subconsciously. Iād argue that this is a good thing.)