Javascript in Page or External .js

Which is best?

[sinclasc]

Guys,
When using javascript, should I just paste it into the page where needed, or use external .js files?

Thanks in advance,

[Lexur]

How many pages? 50? 500? 5000? 50000? 500000?

I supose you have no more than a few dozen pages. If you have some thousands, you'll knew the answer.

[kaled]

If the script is designed for a specific page, I embed it, but if it is shared (or may be shared in the future) then I use external .js files.

Kaled.