I attach anything that changed....and that almost *always* includes the F 1040.  Otherwise, why would an amendment be needed?

I do not attach the 1040 but do include the original and the corrected copies of everything that has changed.  Many years ago a thoughtful client gave me a red stamp that says ""Information Only Do Not Process" that is stamped at the top of each original page.

I have never attached the 1040.  I have never served any jail time and my clients are still walking the streets.  At least the ones that can walk ---------------- when you have been doing this as long as we have, you do watch your clients age.  Of course, we never age

My boss used to send the original return with INFO ONLY written across it, until I convinced him they already have the original, we don't have to send it again.

I'm with Jeff and Jane.

FYI From the IRS instructions for 1040X.  Assembling Your Return
Assemble any schedules and forms behind Form 1040X in order
of the “Attachment Sequence No.” shown in the upper-right
corner of the schedule or form. If you have supporting
statements, arrange them in the same order as the schedules or
forms they support and attach them last. Don’t attach a copy of
your original return, correspondence, or other items unless
required to do so.

Ugh.  It's just now sinking in, all of the idiotic new schedules that might have to be attached to a 1040X now.

yep, just had one that forgot a Ed Jones brokerage account, so not only do we attach the Sch B and Sch D and 8949, but the Sch 1 and Sch 3 also, since there was some foreign tax credit on the dividends.

IF I have to do one (I avoid amended returns like the plague...)  - I might just print the whole damned return & send it.  Jeez.