Train as you fight. Fight as you train. If that is blue jeans with a spare magazine in your back pocket, you are good to go. Developing skills is why we train.
Ill give that an Amen…
If you normally wear flip flops and board shorts around chances are that will be what you end up fighting in. I doubt any class will allow you to wear board shorts and flip flops but IMHO you should keep it as real world as possible.
If you go to work in a suit and you concealed carry. Try and wear your suit during training. who cares if you look like a dufas. haha
I wear a pair of boots and jeans to work almost every day. When i go to the range I wear a pair of boots and jeans. I do use a molle padded belt while at the range. but I also keep that thing pretty close to me when not at the range as well.