Here's my dilemma - Counting back 90 days from the 3rd anniversary of when my wife entered as a LPR comes to 29 July. First mailing day would be 30 July. Rate increase is on 30 July. If I get it postmarked on Saturday, July 28th, will they send it back for being 91 days (one day early)? I have a hard time believing that they would, but I have also heard horror stories of people getting forms returned for being sent too early. Will they quibble over one day?

Sherlock

I personally don't know for sure, but I saw some members posting that yes they do send it back even if it is mailed off one day early. Once again, I personally don't know if it is really true or not...knowing immigration and their ways though, I am afraid they were right.
Looking at the new fees and how bad they increased I think I'd try and mail it anyways....

What was the date on her first greencard?

That is the date you count from - not the date she entered.

I think it depends on the visa you entered with...

I came in with a CR1 visa......and the date on my first card is the same date as the day I entered...

Oh Ok Marilyn. Thanks!

Yes it most likely will be returned. There have been people that have had their application returned on the EXACT 90 day mark as well. So you really should wait a few days to a week to make sure. Either way, sending it in even a day early will most definatly (99%) have it sent back and you will need to re-make out the checks and such for the new cost...