If you care to keep your knives in "good" condition, you first have to decide what "good" means to you. If you carry a cutom knife you will scratch it, you will drop it, you will get it gunked up with dried grapefruit juice, etc. When you sharpen it too late at night or too drunk, you may scratch the blade. You can clean, polish and sharpen a used custom knife, but it won't be pristine.
Right now I have in my pocket a 25 yo custom Mike Franklin small pocket fixed blade with steel bolsters and paper micarta scales that I bought used for $65. It shows it's age in scratches, yellowed micarta, and a past regrind by Mike. The part of the handle exposed to the sun is a slightly different color due to the old micarta. I sent it to Mike for a sharpen and polish about 7 years ago for $25. Sheath was lost before I bought it. You can see one pin on one side of the bolsters. However it is still shiny, clean and has a new sheath made by me. I consider it in "good" condition for a custom knife that has been used for 25 years.
I store it in the sheath because the knife is stainless and the sheath it's made of premium gun leather and have never had a problem.
