To calculate 70-year property ownership when buying a second-hand home, determine the original purchase date of the property and subtract it from the current year. For example, if the home was bought in 1953, subtract 1953 from 2023 to get 70 years of ownership. This calculation helps assess tax implications, as some jurisdictions apply reassessment rules after a specific ownership period.

The 70-year metric often relates to property tax policies in states like California, where Proposition 13 limits annual tax increases to 2% unless a property is sold or changed ownership. After a sale, the new owner’s tax base is typically set to the sale price, but long-term owners may benefit from lower assessed values. Data from the California Board of Equalization shows that homeowners who retain properties for over 30 years save an average of $150,000 in cumulative taxes due to Proposition 13’s protections. Extending ownership to 70 years amplifies these savings, as the assessed value remains capped at the original purchase price plus minimal annual increments. However, in states without such laws, taxes may adjust annually based on market value, negating long-term savings. This highlights the importance of state-specific research before purchasing a second-hand home.