It will get dirty over time. We have had a very expensive set for 10
years ... and I think it looks kind of crummy now.
We don't eat or drink on our leather furniture, so that helps. The
worst culprit seems to be dust ... it accumulates over time even though
you can't see it like you would on a wood surface. I would recommend
dusting your leather furniture regularly.
The other big problem for us has been SUNLIGHT. Ugh. It causes uneven
fading and hardening of the leather. We definitely would have
benefitted from closing blinds when we were not home.
Leather cleaners are effective but I think I have waited too long
between treatments (1 or 2 years at times, I'm afraid to admit.)