Minecraft: would it be cool if?

If anything you build/craft had a life span. Everything you build would eventually decay, then you have to replace those blocks. I'd imagine the life spans to be long, so that you aren't replacing blocks all the time. And the blocks change appearance slightly as they decay.

Some players would think that it was annoying. So you would have to be able to toggle it.

Yea that would be awesome in single player, but on servers it would be annoying having to replace blocks.