It's not always your planter's fault if you get poor emergence and a poor stand. The most perfectly maintained and adjusted planter will produce poor results if:
-the combine's straw chopper left residue spread unevenly. Bean chaff in particular, if left in swaths, is white and reflective enough to keep soil beneath those swaths several degrees cooler than adjacent bare, black soil. There can be a day or more difference in emergence between the cooler soil and the warmer soil. Not much can be done in the spring to alleviate swathed residue, except to make a vow to pay closer attention to the straw chopper's spread pattern during the next harvest.
-if anhydrous was applied last fall or this spring at a slight angle to the rows, every time a planter unit crosses a knife mark that unit will temporarily plant its seed an inch or more deeper than normal. Multiple passes with a field cultivator at angles to the anhydrous marks MAY fill and firm the soft soil in the knife trenches, but who wants to spend the fuel and time to make multiple passes? Not much you can do to correct that problem at planting, but don't blame the planter for ragged planting depth and uneven emergence that's actually the fault of the anhydrous applicator.
-Ruts. Whether they're from anhydrous tanks or sprayers applying pre-plant herbicide, you shouldn't blame planters for not being able to penetrate and maintain planting depth in ruts that average 4 to 6 inches deeper than the surrounding soil. You say four- to six-inches sounds extreme? You'd be surprised how deep the average ruts from anhydrous tanks or sprayers are even in dry soil. Filling wheel tracks with a diagonal pass of a field conditioner can help, but doesn't solve the problem of compacted soil beneath the track that stunts seedling root development.
-Field cultivators/conditioners that start planting season leaving fields tilled like a garden often leave a rougher result by the end of spring tillage. Shovels get worn, shanks get bent, levelers lose tines or get out of adjustment. Planters that planted picket fence populations at precise depths the first week of planting end up pop-corning seed spacing and spewing seeds at a range of depths by the time the last fields are planted, simply because they're planting into ragged, rippled seedbeds. If you look back at your planter and see seed boxes hopping up and down like a "Whack-A-Mole" game, the resulting poor emergence and final stand isn't the blame of the planter--it's because the uneven seedbed kept the planter from doing its job well.
The point I'm trying to make is that everything a planter does is tied in some way to other tillage practices, heck, even to the way the combine was operated last fall. When you're scouting fields this June and trying to figure out the causes of poor emergence and poor stands, don't blame the planter for trying to make a silk purse out of a sow's ear when it comes to soil conditions.
Weekend Update: Corn-Beans-Wheat-Cotton-Cattle-Hogs
All other items on the list pailed in comparison.