I've had to reduce the amount of yeast in most of my recipes recently... May wild yeast be the cause?

I've been baking at home for several months already and, recently (it started a month or two ago), I've had to reduce the amount of yeast in most of my recipes because the dough would ferment too rapidly. I've read somewhere (if I recall correctly, it was about King Arthur's bakery) that baking regularly can have this effect, since wild yeast becomes a lot more present in the air.

I'm not baking everyday, but I do bake a minimum of once a week and I'm wondering if anybody else had this happen to them...

thanks!