For many investigators their handgun is their primary weapon. Consequently, it must be the most effective tool they can have. Here are some thoughts on the selection process of both the handgun and the ever-important holster it's carried in. These aren't necessarily rules set in stone, but things to think hard on as you go about your daily chores.
The Basics
There are four elements affecting the carrying of a concealed handgun by plainclothes officers. Consider them as points of interest that should be attended to in detail. To fail to do so may have the gravest consequences.
Concealment works in opposition to comfort and speed but is necessary for low-profile work. The degree of concealment is usually based on the type of work being done. Over-concealment may lead to a case of, "I can't get my gun." Holster selection is important to the drawing platform, as well as the clothing selection to cover it (concealment). All parts work as a whole, helping to build that "drawing platform."
Comfort works in opposition to concealment and speed. Comfort may not be important to the task at hand, but if it's more comfortable you'll wear it more often. No method is perfect so learn to work with your particular selection. The choice of a flat, smaller handgun will help, but don't sacrifice caliber effectiveness. Comfort levels should be judged from all positions normally assumed during the day, whether it be standing, walking, sitting or driving.