How are changes to Template Variables reflected throughout the site?

Okay, just wondered about this as a heading in a TV was different than the others.

Say I have a site with these pages...
1
2
3
-4
-5
6
-7
--8
-9
--10

and I create a TV with an @INHERIT and some code or text and place that directly in my template.

Then I modify it on page 2 and 3, and therefore, pages 4 and 5 also reflect those changes due to inheritance from page 3.

Now I decide to change the TV itself, adding some text to it.

Where all will it be changed, or not changed? I would assume that pages 1, 6-10 will all reflect these changes, but are pages 2-5 unchanged? And if so, what if I now want them to reflect the global change to the TV, is there anyway to reset them to get them back in sync with the rest of the site?

Any answers or pointing me to the information much appreciated.

cheers