When applying to a new college, is it necessary to request transcripts from every school?

Just request that the schools send the official transcripts directly to the college you’re applying at. That should satisfy any requirements they have.

Yes, every school I know of will want transcripts from any college you have attended.

Yes it’s especially helpful when you can prove you fulfilled a requirement already.

Yes, most schools require the transcripts sent directly from the relevant school, to prevent falsification.