Audio equipment, like everything else, is matter and matter is energy. Energy is constantly changing, even though the rate of change is too slow for us to perceive. On one level, our systems are different from day to day, hour by hour, minute by minute, second by second. Entropy.
Now whether these changes on an atomic (sub atomic) level can be pecieved by listening to music is debatable, these changes occur. Nothing can ever be exactly the same as it was at another point in time.
Temperature, humidity anything different in the air will of course change the way sound waves travel. Even the most rigid enclosure, stiff cone or soft dome is not immune to expansion and contraction, moisture, etc... We can all agree and scientific fact supports a speaker in 95 degree 90% humidity will sound (function) differently than the same speaker in 40 degree 45% humidity.
There are so many factors acting on each and every part of a system and within the components themselves. The compliance for a cantilever is disintegrating, motor/ spindle bearing wear, capacitors are degrading, copper is oxidizing and so many other degradations beyond our control. Can we hear these effects? Yes, but only when we compare one extreme to the other. Not the minute changes day to day.
Simply put, though facts do support changes in function from one day to the other, what we consciously think about the sound is not what we actually hear. The ear is an amazing tool for converting sound to information. The conscious mind is notoriously bad at analyzing it.