If you look back over the past several years of my really good scoring rounds, one of the most often-overlooked aspects has been that my approach shot yardages fell on reasonably good numbers.
And although I'm usually fine with playing a 3/4 shot with a longer iron, a lot of times it's situational as far as hole locations, how much green I have to work with, potential forced-carry situations, etc.
My usual trouble area is when I'm facing a mid-iron (170-175 yards) approach downwind with trouble in the front. Going with less club to account for the wind requires a perfect strike, and going with the right club generally means I'm off the back and facing a very long chip or pitch shot. If there's no trouble in front, not a big deal. But if it's a forced carry, most of us instinctively try to help the ball get in the air at impact, which is typically commensurate with jerking off a rabid mountain lion with 50-grit sandpaper.