If I'm only using 1 movie/episode (or maybe like up to 3 idk), I put the source right up in my NLE and clip from there.

With more than that, my (former) NLE would lag and honestly it gets unwieldy, so for editing shows or a bunch of movies I'd rather clip bits of scenes (up to 1 min in length) I want to use first and then refine subclips in the NLE.

I also keep my sources on a external hard drive.