I see no reason why we shouldn’t keep the same passport number. I don’t really worry about the number being compromised by long term use. Outside of foreign travel, flying or cruising, or as part of my Federal government security clearance I have never been asked for or provided my passport number for any loan, credit card, etc. I might have provided it to the state as part of the RealID process but don’t recall. Point is unlike my Social Security Number and state driver’s license number my passport number is rarely used.