Life is so much easier these days. Before the proliferation of screw-in chokes, changing choke constriction was much costlier and involved machining. Back then, the gun maker offered several barrel length and choke combinations, and you selected from what was offered. Typically, the longer the barrel the tighter the choke. We've all heard of the grandfather's old goose gun with it long barrel and really tight choke, or the upland gun with it's short barrel and open choke. SxSx and O/Us were a little better, they offered two chokes. Typically the second barrel was tighter than the first. A double might be choked IMP/MOD or MOD/FULL. The double barreled goose getter could be the legendary FULL and FULL.
Many folks needed a middle of the road gun, so a medium length barrel and a MOD choke was the answer. It was the all purpose shotgun. The same is true today, if you can have only one choke, then MOD is the one to go, unless you have something specific in mind. For HD and slugs, CYL or IMCYL is probably best. If you're looking to shoot ducks and trap targets, then a full choke is your obvious choice.
JerseyDrez, there's nothing wrong with shooting everything with your MOD choke -- it's the all-purpose choke. However, if you find yourself specializing, then you'll want to evaluate your choke selection. Shooting skeet with a MOD choke can give great satisfaction when you vaporize targets; but, it's demoralizing when you totally miss the next one. All the while, the guy following you is getting them all with his SKT choke.
Yes, additional screw-in chokes can be costly; but, it's very little compared to the cost of having a fixed-choke gun changed. Before you balk at the cost of a new choke, or two, consider the comp skeet shooter with 2 or 3 chokes for each barrel, per pair, of 4 different gauges. You can easily invest in 2-dozen chokes! It's no wonder that Briley, and his brethren love skeet shooters.
Originally, Brileys were designed to be installed in comp guns with expensive thin-walled barrels. Obviously, the thinner the barrel the greater the chance of messing it up while installing screw-ins. Where others feared to tread, Briley was successful. If you've got a typical thicker barreled shotgun, you don't need to pay for Briley's precision. Get a generic choke (specific to your gun) at quarter to a third the price of a Briley (or other premium screw-in). If you decide to change to a high grade gun, then you'll want the Brileys.