Multisite Module Update Being able to update the shared modules folder in a multi-site Drupal installation is amazingly easy, but I am wondering, what are some best practices when it comes to that?

Updating modules on a live environment when multiple sites are affected can be bad if a module has some sort of bug or if it's incompatible with something you were unaware of, correct? Usually we like to perform quality assurance on sites after a module update has been performed, but that starts to become a hassle once there are many sites under one core.

Assuming the sites/all folder is synchronized between development and live environments, pushing a site live is specially an interesting experience - since we want to make sure that all of the modules are updated. Sometimes these modules are in the shared modules folder, meaning it would affect every remaining multi-site as well. Then, in that case the only solutions I can imagine at the moment would be to either:

Push the site live without updating any of the shared modules - Perform updates on the live environment periodically when everyone is available to do Quality Assurance.
Perform module updates everytime a new site is pushed live. In this scenario, quality assurance would have to be performed on every site under multi-site - every single time a new site is pushed live.
Any input would be appreciated. Thanks for your help, guys!
I always run with a Dev mirror copy of the Live site and test all modules here before updating the live site with those modules, do this and test the site thoroughly. Make sure the dev and live environments are identical or as close to identical as possible.