Stress can do it (blood pressure).
And if it’s humid out, or air conditioning too cold, the wax can get slimy or dense and seal up the hole for a bit.
It could be worse things but it’s a good start anyway.
If nothing else, having squeaky clean ears will make it easier for the doc to look into it for any mechanical problems. Sort of like cleaning the car before getting it detailed or brushing your teeth before the dentist.