Traditionally, yes we release at the end of the week before the launch of a new product.
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Previously in the early days of Sims 3, we would release both the basegame patch and the product at the same time. 10:00am. Early enough that the team was all in office and ready to test.
However, this causes a few issues. If players in Asia, Australia, Europe, etc bought the physical copy, they were fine - there was a patch on disc. Not the most updated patch, but one that brought the basegame to a compatible version. If players bought digitially, however - they needed the coordinating patch to move the basegame to a compatible version. Buy the game on release day and not play it til later? No good.
Also, if the patch turned out to be bad (rare, but has happened) we were scrambling to fix it - especially because again, digital players wouldn't be able to play their game.
So then, (I think after a particularly bad streak of patches) we decided to release the patch early so we could have QA verify everything went well. We realized it solved a bunch of the above issues and players got excited to see the basegame changes through the weekend.
We also used that emergency time in at least one case. We had a bad patch release on Thursday, rolled it back and engineers fixed it that day, generate patches overnight, test on Friday, run it through certification and additional testing Saturday, submit patches to be hosted on Sunday (while testing more just in case), and release the patch on Monday at 10:00am - a day ahead of the official release, and just in time for Asia.
So we stuck with that schedule. End of the week for patches with products coming out on Tuesday. It's not set in stone, but I think it works for everyone.