Foam air filter disintegrating, clogging carb, alternatives?

I know on my dirt bikes I'm replacing foam filters every 2-3 years now. In the old days (I grew up riding in the 80's) they lasted a lot longer. I don't remember ever replacing a foam filter in the 80/90's, just lots of cleaning and oiling... Something has changed either with the filter material, or the oil. I dunno, but they sure disintegrate quicker than they used to.