Sample Copryrights, Public Domain?

I have a few questions about samples and copyright, I would like to keep it simple.
When a record becomes public domain? And a movie? where do you find good sources of “legal” material?
I suppose that its not the same in all countries, for example lets talk about USA (lot of movies).
I want to use a lot of samples (movie snipets, anime fragments, etc) but I want to know the legal aspects.

If you’re not selling stupid amounts of records, don’t worry about copyright.

Yeah, don’t worry about it.

USA has some strict laws.

It doesn’t matter where the creation was produced which you are sampling, rather than where you live and where you sell/distribute your music. Many EU countries for example don’t even have a well defined concept of Public Domain, and some copyright organizations actively protect some creations which are marked PD in USA.

On the other hand, fuck all this. Just sample what you want. Getting sued for this is highly unlikely. Worst that can usually happen is that they tell you not to distribute some specific song.

Sampling is illegal.

If you want to be legal, you need to clear all samples with written permission from the copyright holder, sometimes royalty agreements.

Drugs are illegal too.

Well, that isn’t completely true. Sampling Copyright material without permission is illegal. There’s also Creative Commons, etc.
But yeah, it seems a pain in the ass in most cases.
Thanks for the answers.
Fuck all this : )

Another similar questions (just to know it ): if I want to recreate (programming) a riff, for example a 3 chord riff from The Stooges, I need permission? Or theres some limit about what is to rip of (1 bar, 2 bars, etc).
And if I want to make a cover? Obviously citing the authors.

In France, artistic achievements fall into public domain 70 years after the artist’s decease.

i quite recently heard that the guy who drummed in the amen break died in poverty.

So did Beethoven