Some interesting perspectives on this thread.
My DS1 is un-coordinated, and his personal organisation is a nightmare. DH is very similar.
When I have mentioned it to teachers they have tended to say "Oh, he's just a boy," as if clumsiness, vagueness, forgetfulness, and OK-I've-lost-a-library-book-but-why's-that-my-problem-ness, are all part and parcel of owning a pair of testicles.
DS1 is very good academically and so I think his teachers will put up with more disorganisation from him due to "absent-minded professor syndrome."
However, secondary school is going to be a different matter:
Lose your homework - detention.
Lose your lunchbox - no lunch.
Lose your pencil case - have to buy a pen from head of year.
Lose your school jumper - get cold as uniform shop hardly ever open.
Come in late for lessons habitually - detention.
Forget books - detention.
I do worry. "Silly me, what am I like?" will only do for a few years.
At the moment I am encouraging him to know his strengths and limitations. I say that he is clever but as he is a bit forgetful he should make lists. As he is a likely to drop things, he should carry a bag to school rather than trying to carry everything in his hands. It's excruciatingly slow progress, but I have to try as, although I accept how he is, I'm sorry to say, children do not get accepted for what they are in secondary school, and it worries me sick.