Correct upgrade procedure for extensions and themes

Question

When a newer version of an extension (or theme) you are using is released, what is the standard way to update/upgrade a site with it? (assuming that the extension/theme uses Magento Connect)

Can I just install the newer version overwriting previous files?

Or should I first uninstall the previous version, then install the new one?

Does it make a difference if the installation is via Extension Key or Package File?

I've found a lot of information about upgrading Magento itself, but virtually nothing about extensions/themes!

Answer 1

what is the standard way to update/upgrade a site with it? (assuming that the extension/theme uses Magento Connect)

To answer your first question, you should never do this on your live site, and I would advise that you NOT use Connect to do any updates. The best practice would be to have your entire codebase in a repository and to update your files then deploy to your site. I realize this is this not realistic for everyone but you should start with having a test site you can practice on.

Can I just install the newer version overwriting previous files?

Yes, as long as you test first

Does it make a difference if the installation is via Extension Key or Package File?

No

I would never upgrade a theme on connect.