I've conceal carried for 38 years and pretty much the only exceptions to daily carry have been work hours for three years on a non sworn law enforcement federal job in DC, and vacations over seas.
I started conceal carrying a full size 1911, evolved to a Hi Power, went back to an officer framed sized 1911.
Then I diversified to a wider range of hand guns including 2 1/2" and 3" Model 13, Model 66, 686+, SP101 and K6R revolvers, as well as a CZ 75 Compact and CZ 75 Compact PCR, with occasional a carry of a Beretta 92 Compact and a few different lightweight commander sized 1911s.
Lately I've found a Taurus 856 Executive (after the poorly designed grips were replaced) to be a near ideal revolver when .38+P is adequate and I don't have a need for .357 Mag. I've also found the Girsan MPC35 compact sized Hi Power to be a superb concealed carry handgun.
The irony of course is that neither of those latter guns are what you'd call upscale or expensive. But they have both proven to have good combat accuracy and are very reliable.
I also have a Beretta 80X and a Kimber Micro 9 that I carry when smaller handguns are required for better concealment. I actually have two of the Micro 9s but much prefer to carry the newer one with the rubber grips and the mini compensator as it's much more controllable at speed resulting in much faster doubt taps and failure stop drills.
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The common denominators, and for me the defining requirements for concealed carry, are that all of the above are small enough to readily conceal, and are also large enough to shoot effectively - both accurately and at speed.
I do have a few small handguns including a Kimber Micro, Beretta Tomcat, Beretta Bobcat, a couple older Beretta 950 series pistols, that I will carry when nothing larger will do, and or as a backup. But again they are also well balanced in terms of size and shootability with their smaller cartridges.
If you can't shoot it fast and accurately, or it recoils so much you won't shoot it often enough to remain proficient with it, it's a poor choice for every day concealed carry.
Similarly, if it is so large and uncomfortable that you won't carry it from the time you get dressed until the time you go to bed, it's a poor choice for concealed carry.