The Six Lines of a Carrying Figure: What a Home Really Costs to Own
The monthly number is a payment. The carrying figure is what it costs to own the property for a year, averaged across the things that don't happen every year. Every long-owned property has the same six lines — what differs is which ones are moving.
This checklist sits alongside our full piece on what this house actually costs to keep, and our broader five housing paths framework.
The Six Lines
- Debt service. Mortgage principal and interest, or nothing if the property is owned outright. Level on a typical fixed-rate mortgage; adjustable-rate and other loan structures can behave differently.
- Ad valorem taxes. Based on assessed value as established by the Property Appraiser, at rates set by the county, the municipality where applicable, the school district, and any other taxing authority. For qualifying homestead property, annual growth in assessed value is limited by the Save Our Homes assessment cap — that cap limits how fast assessed value can rise, not the tax bill itself, since millage rates can still change the amount owed.
- Non-ad valorem assessments. Charges calculated by the levying authority using measures other than property value — stormwater, solid waste, streetlights, and improvement district assessments among them. These appear on the same bill as ad valorem taxes and are calculated on a different basis.
- Insurance. Homeowners, plus flood as a separate policy where applicable, plus wind where separately written.
- Association obligations. Regular dues, plus any special assessment, plus what the reserve position implies about future assessments.
- Operating and replacement. Utilities, lawn and pool service, pest control, routine repair — and the annualized cost of major systems that will need replacing, whether or not you're setting money aside for them.
The sixth line is easy to leave out entirely, and it can be one of the largest. A roof estimated to have eight years of remaining useful life creates a replacement obligation that can be expressed as an annual planning figure, whether or not the household is setting that money aside.
Can you fill in all six lines for your property?
Knowing what the property would realistically be worth is the other half of the picture — the two figures together are what make any comparison meaningful.
Frequently Asked Questions
Which of the six lines tend to change the most over time?
Insurance, association obligations, and replacement costs can be among the less predictable of the six, since each depends on the specific property, the specific association, and the specific systems involved. Debt service on a typical fixed-rate mortgage stays level, and ad valorem taxes move within the bounds of assessed value — including a homestead's Save Our Homes limit on how fast that assessed value can grow, which is separate from what the tax bill ultimately comes to.
How do I estimate the replacement line without a full inspection?
Start by identifying installation dates from the appropriate permitting authority or available records for the roof, air handler, water heater, and electrical panel — that establishes age and history, not remaining service life on its own. Once you have a reasonable estimate of remaining useful life and replacement cost, drawn from a licensed inspector or the relevant contractor, you can convert that future obligation into an approximate annual planning figure.
For the full picture of how these six lines interact and which tend to accelerate together, see What This House Actually Costs to Keep.
Resources Directory
Related reading
- Staying, Adapting, or Moving: The Five Housing Paths
- What This House Actually Costs to Keep
- The Four Conditions for Staying Well
- Who Actually Decides What You Can Do to Your Home
- Palm Beach County Home Value Assessment
About the Authors
Chris and Sue Kull have spent more than three decades working with South Florida families through property decisions across Palm Beach County and the surrounding communities. Their focus is on making the structure of a decision visible early, so the household weighing it can choose on its own terms.