We're building a spreadsheet that lists all the orders we need to ship out in
column A (by order number). Other columns provide data. There are about 500
orders per day.

Each day we add a new sheet and delete the oldest one, so we constantly have
the orders needing to be shipped out for the past 30 days.

I've been trying to find a way to take the orders on the newest sheet and
see if they match orders on previous sheets, then change the color of the
entry number on the newest sheet to alert me that it's an order holding over
from the previous day.

Theoretically, I'd only need to compare each record against those the
previous day.

I can't seem to find a conditional format that works properly and I don't
know all of the VBA-coding functions well enough to do this on my own.

Can someone help?