I once had a client whose return I amended 3-4 times every year. He flitted from job to job, often having 4, 8, 10 W-2s. He'd come in with 6, I'd ask if he was sure that was it and file the return. Next week he'd come in with another, we'd amend and off he'd go until the next week when he came in with yet another. I guess when you work at that many places it's hard to remember where you worked and what you should be expecting in the mail. Gave him credit, though, for never giving up and trying to be gainfully employed instead of discouraged. This was way back at HRBlock, where you had to get those returns filed. Where I am now he would definitely go in the hold pile (along with those whose always get corrected brokerage statements or really late OIDs) until at least April 1.
Jack, why would you not amend unless the tax change is at least $100? Does computer matching have some sort of threshold where those CP2000s don't go out unless the taxpayer owes $100+? When those letters get spit out a couple of years later the interest can double the amount due. And some states will send bills for $1.34. (PA is an exception--if you owe $3 or less they forgive you.) Amendments aren't that hard to calculate (although they take some work to print and assemble and make sure you have the right attachments), you get to charge for them, and it keeps the client from getting a surprise notice down the road. Plus you can do them in the off-season when you're not so busy. Why not?