And, not like you need it, but another +1. I'm in soft clothes daily. I have my vest and plates in an external carrier that I carry with me back and forth from the office to my government car so I have it with me all day.
There's no point in wearing armor all day under your clothes when you're sitting in an office doing contract file reviews, or headed to do a pre-planned interview with a cooperative witness.
If I'm going out to do knock and talks in certain areas, I'll armor up under my shirt, but I'll also usually have another agent along to back me up.
I'm guessing this thread is motivated by the recent blue-on-blue shooting in NYC that resulted in a dead MOS. If something like that happened to me on the way home today (robbery at the gas station while I'm fueling the G-sled or some such), you better believe my FIRST concern after "taking care of business" with the BG is going to be NOT getting shot by responding uniformed LE (with whom I have no means of easy communication)...