Five years ago I couldn’t have told you whether my third property was costing me 80,000 yen a year in upkeep or 480,000 yen. I just paid the bills as they came and hoped the rent covered everything. Once I started tracking maintenance spending property by property, year by year, I found two units that were quietly bleeding six times more than the rest of my portfolio — and I only caught it because the numbers were sitting side by side on one sheet.
With 9 rental properties, some built more than 30 years ago, maintenance costs don’t behave the same from building to building. A system that tells you what each property actually costs, year after year, is the difference between guessing and managing.
Why Property-by-Property Tracking Matters
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When you lump all repair receipts into one general expense account, you lose the signal. A single new water heater at 140,000 yen looks like a normal year if it’s averaged across 9 buildings. But if that same property also needed a 90,000 yen roof patch and a 60,000 yen drain snake job in the same twelve months, that’s a pattern, not bad luck. I didn’t see that pattern for the first six years I was a landlord because everything was tracked as one lump sum.
The Spreadsheet System I Actually Use
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I keep it low-tech on purpose — a single spreadsheet, one tab per property, one row per expense. Each row has five columns: date, category, description, cost, and whether I did the labor myself or hired it out. At the end of each fiscal year I copy the year’s totals into a master comparison tab so I can see all 9 properties side by side across the last five years. It takes me about 20 minutes a month to keep current, and roughly 2 hours in March to close out the year and update the comparison view.
The Categories I Break Everything Into
I sort every expense into one of six buckets. This is the part that makes year-over-year comparison actually useful, because a spike in one category tells you something specific.
- Plumbing (water heaters, pipes, fixtures)
- Electrical (wiring, breakers, lighting)
- Exterior and roofing
- Interior turnover costs (paint, flooring, cleaning between tenants)
- Appliances (aircon units, stoves, ventilation fans)
- Structural and foundation work
When I see interior turnover costs jump 35 percent at one property but stay flat everywhere else, that tells me something about tenant turnover or wear, not general inflation in materials. Materials prices affect every property roughly the same amount; a category spike that’s isolated to one building is a property-specific story.
How I Spot Cost Creep Before It Becomes a Real Problem
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Every March, when I total the year, I calculate a simple per-property average: total maintenance spend divided by the number of units in that building. Across my portfolio that average has run between 38,000 yen and 65,000 yen per unit per year for routine upkeep, excluding big one-off jobs like a roof replacement. When one property’s number climbs more than 25 percent above its own three-year average, I flag it for a closer look, even if nothing looks obviously broken. That threshold has caught two slow leaks and one failing water heater before either turned into an emergency call at 11pm.
I also track the ratio of DIY labor to hired-out labor per property. If a building suddenly needs far more hired work than usual, it’s often a sign the issues are getting bigger than what I can knock out with a wrench and a Saturday afternoon — which is its own kind of early warning.
Turning the Numbers Into Actual Decisions
The real payoff isn’t the spreadsheet itself, it’s what I do with it. Two years ago the tracking showed one of my older properties running at nearly double the portfolio average for three straight years, mostly in plumbing and electrical. Rather than keep patching it, I did a full rewire and repiped the worst bathroom for about 620,000 yen. The following year that property’s maintenance cost dropped back to roughly 42,000 yen per unit, right in line with the rest of the portfolio. Without the year-over-year data, I would have kept treating each repair as an isolated incident instead of recognizing the building needed one bigger fix.
I use the same data at tax time and when I’m deciding whether to raise rent on a specific unit. A property with rising, well-documented maintenance costs makes a much easier case to a tenant, or to myself, for a rent adjustment than a vague sense that things feel more expensive lately.
Keeping It Simple Enough to Actually Maintain
I’ve tried fancier property management software twice and dropped both within a few months, mostly because entering receipts became a chore I put off, and a tracking system you abandon by June is worse than no system at all. The spreadsheet works because I can update it from my phone the same day I pay a contractor, and because the categories map directly to how I already think about my buildings. Whatever system you use, the test is simple: can you glance at five years of data for one property in under a minute? If not, it’s too complicated to survive contact with a busy landlord’s schedule.
That’s the approach I use across all 9 of my properties, and it’s the single habit that’s saved me the most money over the last five years without requiring a single extra tool purchase.
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15 years of landlord experience u00b7 3 apartment buildings u00b7 DIY renovations that saved millions of yen. Browse all articles at diytosan.com
