theme vs. extensions what should be installed first

[BluGallagher]

Im preparing  for a new installation of magento to include multiple themes and extensions.

On previous installs i've installed extensions to the base theme prior to installing 3rd party themes and find that the extensions show in the admin just fine however have NO affect and/or conflict in the frontend of the 3rd party themes until files are copied from the base to 3rd party theme folders(what a PIA and great way to make a ton of mistakes). As we know many extensions require manual installation and that entails putting extension files into the theme folders on the get go. When you install the extensions into the theme folders only ...the only time the extension works on the front end is with that one specific theme ONLY.

So if you should make a new theme and want to change the theme you are then tasked with copying ALL extensions into the new 3rd party theme as well. That task can be daunting to some who have massive amounts of extensions huh. However if you install the 3rd party extensions on the get go into the base, prior to installing the 3rd party theme the front end items of the extension are overwritten by the 3 party theme and the front end affects of the extension are null.

I'd like to be able to use my extensions and test performance to make sure they perform appropriately and are functional with the base of magento as well as in a new themes. Then there after "" i'd like""" to have the extensions work just as well with the themes without having to jumble around and copy and move a ton of files and folders just to see the extensions active when switching from one theme to the other. 

Is this a magento 'THING' ?

I'd like to know what should be installed first, our extensions or themes and is there a method or way to go about installation to avoid having to copy extension files to every new theme that we add to our magento installation?

[Pronto]

This is a potential can of worms, mostly because pretty much everyone and their dog have their own opion about the matter. 

Personally I prefer to install third party themes first for two reasons:

1. Themes usually come with their own set of required extensions. I always want these to be installed first; it's really annoying to find out after hard work of adapting dozens of extensions that your chosen theme causes too many conflicts. Installing themes first makes much easier to resolve those.
2. Installing theme first gives you from the very beginning something that's visually close to the final product. It adds flexibility, making possible to move some features to post-launch phases without breaking a step (it's universally considered desireable to launch as early as possible). You get the feel how far along you are from the very beginning. You can even skip some extension altogether if you find out that a) they do not adhere with design or b) they do not add to the user experience..