Complexity can rise faster than length
Additional systems, machinery, accommodations and equipment can increase service workload even when two yachts are relatively close in LOA.
Berthing deserves early research
Availability and pricing for an appropriate berth can materially affect ownership decisions and should be investigated before purchase.
Professional support is a planning variable
Some ownership profiles may involve a captain or other professional support while others rely more heavily on experienced owners and periodic help. Do not assume one staffing model from length alone.
Maintenance history is critical
Review service records, major machinery, stabilizers, generators, HVAC, electronics, tenders and other systems with appropriate professionals during due diligence.
Model the trips you will actually make
Fuel and transient expenses depend heavily on speed, distance, route and use. A realistic cruising plan is more useful than a generic annual fuel assumption.