All lenses got a maximum of 1000000000 shots, after that it will disintegrate into thin air! *just kidding*
on a serious note,
your lens will have a shorter lifespan (not by shutter counts) if you do not take care of it.
- Fungus infestation if you did not store your lens correctly in the correct environment
- Coating on lens glass wear off if you are introducing liquids or chemicals to your lens glass when you should not.
- AF motor breaks down due to rough usage or drops