I own a fabrication shop so my gear is constantly exposed to grinding dust, welding smoke, etc. I carry my XD45C in a Comp-Tac MTAC hybrid so one side is Kydex and the other side leather. I clean the weapon and holster every Friday night before I lock up the shop. The holster gets blown out with an air nozzle and then wiped out with a shop towel.
The Kydex shell wore though the finish at the top corner of the slide on a section about 1-1/2" long straddling the ejection port in a matter of two or three months. This is tennifer coating or whatever you want to call it, same process used on Blocks so it's a very tough finish. Over the next year or so the sharp edge where the slide is wider near the bottom for the rails wore through in a section about 2" long, directly under the ejection port. This is where my belt is, so it's where the most pressure is.
On the leather side, it took about a year for there to be any noticeable wear at all. The finish is just getting thin at the top corner opposite the ejection port and I think I've been carrying it daily four years or more. From the back of the forward slide serrations forward the top corner has no finish left at all and there are what looks like really tiny rust pits all in a row about 1/2" long. They may very well be corrosion, my holster's leather backer is often soaked with sweat. I have never treated the leather portion of my holster with a conditioner or anything else.
I do not oil this firearm for daily carry as any form of lube does more harm than good in that it picks up abrasive dust which then turns into a slurry like lapping compound. For my use, based on what I see looking at my .45 right now, a Kydex holster would be better than leather because of the possible corrosion starting on the top front corner of the slide. If you're world is cleaner, less abrasive, and less sweaty than mine leather is probably the better choice.
As others have said, I don't care about holster wear on a carry gun. This thing's got dents, scrapes, and scratches all over it as it's been rammed into all sorts of things from cars and backhoes to my tool box, the ground, various door jambs, and just about everything else I encounter in my daily life. Unless it's a weapon that you are only going to carry on rare occasions I would go with whatever holster fits and works best, and is the most comfortable regardless of it's material and potential wear to the finish.