With us, it depends on the client and how often they screw up!  We'll give them the occasional freebie with consistently good clients, but if there are continuing (stupid) problems, we charge them full price every time we make the attempt. 

We DO try to hold on to the document for them if they can just send us a new page -- like a different legal.  I know that "it depends" isn't a clear answer, but you know your clients and you know which ones will put up a stink and which ones will graciously apologize and give you your fee w/o question. 

Alix