How to keep multiple drupal websites up to date I do a lot of web consulting and drupal is my preferred tool of choice. But as I grow, it seems like drupal gets more and more needy. At least once a week, if not more, my inbox gets messages that drupal needs updating, and I have to go and update the dev server, verify nothing broke, and then update the production server, and again verify that nothing broke.

I'm using drush to help me with this, but this is still taking considerable time away from my business, time I could be billing to the customer.

Does anyone have a solution to this? Some way to automate the updates and then a regression test, and if successful, do the same on production?
You could write scripts to do this.  You'd probably want to tie in to the Drupal unit testing module as well.

I can't provide you with any actual examples, because I'm not sure how it would be done reliably.

In my opinion, you're looking at a business problem that can't be fixed with a programming solution.  If I were in your shoes, I would start charging customers an ongoing maintenance fee for upgrades.