Unfortunately, there is no cute, concise answer to quantify "need." Nor can it be said that all factory choke tubes are deficient, for many factory tubes have produced perfectly acceptable patterns.

The whole idea is to bag or break more birds, of course, and first we need to start with hard, round shot and consistent shells. We also have to pattern our guns, for if we don't have a clue what our baseline patterning performance is we won't know if we are improving things, or going the wrong way.

But, if we are willing to do the basic defining of what our shotguns currently do, and are willing to document our changes, there are a few generalities that have held true where an after market choke tube will give us visible improvements.

If our gun is equipped with one of the shorter choke tubes, such as the "WinChoke," Browning standard Invector tubes or the stubby "TruChoke" tubes, the use of any significant amount of constriction in our chokes will be improved with an after market extended choke tube. These give us a longer parallel section to accommodate that constriction.

If our shotgun came with noticeably rough or poorly machined chokes that quickly collect plastic wad material we can dramatically improve the situation with a high quality after market tube. That plastic residue can degrade patterns after just a few shots. This is assuming the use of quality wads, not crummy recycled wads or factory promo shells. Plastic build up should not be a major issue, and if it is we need to fix it. You might think that some of the "wad-retarding" chokes on the market are a generally bad idea due to their propensity to collect plastic; I sure do.

When using a "squared load," a pellet column as wide as it is tall rather than a tower in our shot-cups, we generally have a good performing load if the components are of good quality. Above the "squared load" configuration, pattern efficiency goes down. Yet, greater effective spread is just that. To get the most out of heavier payloads, an After Market choke is usually indicated. Not using heavier payloads for mid to long range field work deprives us of larger effective spreads.

Naturally, some applications need little help in this area, for instance blowing #8-1/2 shot at quail. Pass shooting doves or ducks, or hunting late season pheasant, we need the best we can find.

Larger shot sizes usually benefit from quality after market tubes with longer parallel sections, particularly when hunting with the smaller gauges. Not all 20 gauge guns do well with factory tubes and #4 shot. Longer, better machined after market tubes may make a huge difference. The patterning board can verify this.

As new and better no-tox loads are introduced, such as the Winchester Xtended range shot, and Hevi-13, it is obvious that pre-existing choke tubes are neither designed nor tested to give optimum results with shot materials that did not exist when those tubes were made. To get the most out of Hevi-13 and other recent no-tox pellet materials, after market choke tubes are more necessity than elective.

Low charge weight, light constriction, low velocity, small shot size shot, and promo loads are likely to benefit least from after market choke tubes. Conversely, heavy payload, large shot size, high velocity, moderate to heavy constriction applications can benefit the most from quality After Market tubes. Drop to 20 gauge from 12 gauge and the difference becomes even more pronounced. Your pattern board proves it. What your eyes witness, your mind must believe.