For me it doesn't depend on the client. If they do $500 worth of printing per year, they can go to Kinko's. And I hope they do because I can make quite a bit more money in the reclaimed time, and they'll probably like the "immediate" service better. If they do $50,000 worth of printing per year, we've discussed print-ready artwork.
That being said, it depends on how broken the artwork is. If I can fix it in 5 mins or less (which I generally can), it's fine. If one image is low-res and they can supply a high-res version of it, I can swap it out. Solid color background on a business card with no bleed? No big deal. Probably. Photoshop can be your friend
Time is much more valuable than money, and I can't afford to give mine away for free - time or money. I had a lady tell me a while back that her jobs couldn't be printed on an AB Dick because those can't produce high enough quality for her taste. I'm sure she'd do a decent volume of printing, but I don't have time for stupid people. Somebody support me on this one - maybe she's on this forum hahaha! Had a guy that needed to come "inspect" the color on digital prints to make sure it was right (which, of course, it never will be). I told him a color match is $35 if he provides the color, otherwise $90/hr. Guess what? He pays $90/hr. For his short runs, sometimes the "color match" fee exceeds the cost of the printing! None of the customers I don't want to lose mind paying a little more; they like me because of the exceptional service.
Bottom line? Same concept as you have with bad clients - charge yourself out of business. They'll stop wasting your time one way or another: either they go somewhere else or the get print-ready artwork. Either way, you win because your time is more valuable than their money. Customers can be replaced; hours can't.