sef or non sef for internal hyperlinks

Hi folks, newbie question time here ... 
When I make some text into a hyperlink that will link back into my own site, I usually think to navigate in my browser to the page I want, then cut and paste the url into Joomla's WYSIWYG editor.
My question is, does it matter to use sef or non-sef urls to do this? These are all internal links: some lead to text that needs to be indexed, some lead to unimportant pages like the login page, others are for registered readers only.
So, do I just copy whatever is in the browser, or get the non-sef url from the menu manager? Does it matter? 
Thanks for your help on this...

www.sakic.net/support/faq/sef_advance/#23

Thanks Saka,
I should have checked the FAQ again, sorry.    I'll just quote a line here for anybody else who reads this question to get the info out, and they can follow your link for the full details.

When you create an internal hyperlink in your Joomla! or Mambo (4.5.1 or higher) content always enter a relative, non-sef URL

Okay, just to be sure here..

You say:

Note that some editors might override your link. You may want to turn the editor off or view item's HTML code to make sure the link is relative.
...
To find out the non-sef address of the page you want to link to you might want to disable SEF for a moment in your global configurations.

So, when making a hyperlink to an internal page, or a menu item to an internal page, we need to use a non-sef url. To be sure we have got the right url we need to:

• Disable sef advanced.
• Make sure the WYSIWYG editor isn't messing up the url.
• And, here is where I am not sure, disable Joomla's sef feature too??  ???

Thanks for your patience 

Just find out the non-sef URL and enter it making sure the editor doesn't mess it up. That's all.