Only way for a knife to stay pristine is not using it. Or even better, do not take it out of the original package.
Handle is not going to be destroyed if that's what you are asking. Scratches? Well, sure. Knife will get scratched sooner or later, it will also happen during use, whenever you put it on a hard gritty surface, etc.
Some people do not carry any other stuff in their dedicated knife pocket. I always carry in my front right pocket with a clip and usually don't carry much crap in that pocket. IF anything, it could be a thin wallet, which being leather, does not harm the knife in any way. But I have carried keys and pocket change at times and I didn't ruin any knives.
Regarding the no-clip route, beware that the knife will probably slide down and sit flat at the bottom of the pocket. Probably uncomfortable if pants are tight and forces you to reach with the whole hand to grab it.
If you want to carry clip-less to conceal the knife from others view, consider carrying clipped inside the waistband slanted. The belt of your pants will cover the clip and unless you tuck in the shirt/t-shirt too tight, the protruding end of the knife will not show either. Blouse it a bit and done. If you don't tuck it in, even better.
Mikel