Cliff, two bits of advice.
1) Do not change the inner air filter until necessary. More frequent changes only increase the possiblity of introducing dust and dirt into the intake. A "slightly" dirty filter filters better anyway. If yours is anything like mine on my TC 40D, the inner hardly shows any evidence of even being used.
2) For the engine oil filter, use a Motorcraft FL-300 or AC or Puralator equivalent. I've done this for over 12 years on my old Ford 1720 and now on the 40D. As far as overall construction, filter media area and rating, it surpasses anything from NH.