I don't believe there is a such a thing as a silly question.

I buy mine in the 50 foot sections that I get a the local sporting goods store because that's what's readily available when I want it.

I keep it in that length until I need it for something and then let necessity determine what length I need.

If I end up buying a bulk spool of it in the future (not a bad idea), I will probably cut off a few 50 foot sections to carry mostly because that's what I'm used to dealing with.

(we Homo sapiens are consistent if not anything)

I'm always open to suggestions though.