American tourist here. I understand the 180 day scheme, 90 days in (non-consecutive), 90 days out (consecutive).
Here’s the question: I enter the Schengen area on Jan 1st and leave the Schengen area on Jan 31st (30 days) leaving me 60 Schengen days unused. Can I wait outside the Schengen for an extended amount of time, say 5 or 6 months, and then arrive in the Schengen area with my 60 days still usable?