Positive

Negative

Started for a long time

For

I’ve been reading that book for ages. 


I have read a book in ages. (X)


Finished for a long time

In

That’s the worst book I’ve read in ages. 


That’s the worst book I’ve read for ages. (X)

For/In

I haven’t read a good book in ages. 


I haven’t read a good book for ages.


I haven’t been reading that book for ages.


I haven’t read a book in ages.