When should I amend my e-file return? Just received a forgotten w-2 of my wife's. It's only for $700 additional income and would reduce my fed refund by $150.

You can amend any changes once the IRS has accepted your return. If they reject your return, then you will have the opportunity to make necessary changes, add anything that was forgotten, and resubmit your return. The instructions to amend are below:

https://ttlc.intuit.com/replies/3288565