I clean mine every week, usually the evening after I shoot. Glocks are so easy to clean, I can't see any reason to leave them dirty. It's probably my imagination but mine seems to shoot better when it's nice and clean. I think it's happier!
I clean my G26 about every 500 rounds or so, typically every few range sessions. Even at 500 rounds, there's not much "dirt" to remove.
At the other extreme for me, is my Ruger Mark II .22LR target pistol. I clean it every time I shoot it, even though it's much harder to clean. It just looks filthy after a shoot and is twitchier than a Glock.
I would not carry a dirty gun. Say you are in a mall and there is a shooting, you are carrying, but do not shoot. In this situation it is nice to have a clean gun to immediately establish you did not fire.
Hello. No! This will not work in tight pockets. They must be loose, "Docker" type pants/pockets. There is a bulge, but in a year no one's noticed.
No discernable gun outline's visible, but I believe the package would just be too bulky for jeans.
I clean mine after each shooting session, no matter how many rounds I put through it. I know that Glocks will take a lot of abuse, but why risk having your gun fail in an emergency, becuse it was dirty. Remember, Father Murphy and his law rules the universe!!!