My K3 was bought November of last year and it still looks like the day it was bought. No Rubbed keys or anything but I don't use the keyboard much. So I expect it to last a long time.
I don't take mine out of the house and it sits on it's own shelf. I keep mine in a lighted cover when not in use.
I've only taken it on one trip to the In laws and it was transported in a plastic tote with my clothes. We didn't want our neighbors to know that we were going on a trip so instead of suitcases we used a tote.
I am known to baby my stuff but I think the K3 could take more abuse and still work fine but don't ask me to do it.