How do passive investors actually track what's happening across units they don't manage themselves

Reserves draw-downs will blindside you if you're not watching that line separately from OpEx.

Tucson multifamily at that size, the line item that usually doesn't come through cleanly is water/sewer when it's owner-paid, because some managers bury it in utilities and some break it out and the delta can be $8k-$12k annually on a 48-unit if there's a billing lag. If both properties are master-metered you want that as its own row or you'll never see a real comparison on operating expense ratio. The other one I'd add early is concessions, because a manager running a month-free-rent special to hit occupancy looks great on vacancy but the effective rent per unit is a different number entirely.

Vacancy, NOI, and delinquency are the right three, but the one that sorted me out was tracking concessions separately, free months, reduced deposits, whatever they're giving to lease units. It inflates effective occupancy and you won't see it in a simple rent roll unless you pull scheduled rent versus collected rent side by side.

The thing I'd want confirmed before you're locked into that 72-unit: does the prospective manager report on a cash basis or accrual, because that alone can make NOI look 8 to 12 percent different between two properties in the same zip code.

The one that bit me hardest early on was turnover cost per unit, because it doesn't show up clean on a P&L. It gets buried in maintenance or make-ready depending on how the manager categorizes it. When I started pulling it out separately I realized two properties I was comparing had wildly different numbers that vacancy alone wasn't explaining. The other one I'd add is collections-to-billed ratio rather than just raw delinquency, because a manager can report low delinquency while quietly writing off balances or not pursuing collections aggressively, and you won't see it unless you're watching what was actually owed versus what came in. For your standardization problem specifically, I'd just build the master sheet yourself with fixed row definitions and then translate whatever format each manager sends into your rows manually, takes maybe 30 minutes a month once you've done it twice. The friction of doing it by hand is actually useful because you catch things you'd miss if a tool just ingested the file automatically.

Your three are fine but they're all income-side. The thing that quietly distorts your NOI comparison between two properties is how each manager classifies repairs versus capital expenditures. One manager runs a $4,200 roof patch through maintenance expense, the other capitalizes it and you never see it hit the P&L at all. So your 48-unit looks like it's bleeding on operations and the 72-unit looks lean, and actually they just have different conventions. You won't catch it unless you're also pulling the capital account summary every quarter and cross-referencing what moved.

When I was setting up my own tracker I forced myself to pick one classification standard before I had more than one property, and I went with a simple rule: anything under $2,500 is an expense, anything over is capital, regardless of what the manager calls it. Then I reclassify manually when I enter their numbers into my sheet. It adds maybe 20 minutes a month but the two columns actually mean the same thing now. For Tucson specifically I'd also add a water/sewer line item as its own row separate from utilities. That market has had some significant rate increases the last couple years and it moves independently of everything else, so if you're blending it into a catch-all utilities figure you'll miss it until it's already a pattern.

The effective rent versus scheduled rent point is the one I'd put at the top of your list, and the gap between those two numbers told me more about what was actually happening in a property than vacancy rate ever did. Concessions, move-in specials, partial payments the manager accepted and called "collected," all of that can make your vacancy look fine and your delinquency look fine while your actual cash position quietly degrades. At the 48-unit level it might be a few hundred dollars a month of noise. At 72 units with a different manager who has different definitions of "collected," that gap can run $4,000 to $6,000 a month and your spreadsheet will look like both properties are performing comparably when they are not even measuring the same thing.

The version that went wrong for me was a 36-unit in Phoenix around 2021 where I was tracking NOI and felt good about it for probably eight months before I realized the manager was netting out concessions in a way that made the rent roll look cleaner than the bank account. By the time I dug into it I had about $31,000 in accumulated concessions that never showed up as a line item anywhere, they just lived inside "gross potential rent vs. collected" as a math problem I was not doing. What I would add to your three: maintenance as a percentage of revenue tracked monthly, not quarterly, because that is where deferred maintenance shows up before it becomes a capital problem, and it is the one line that almost never gets reported the same way across two different managers without you forcing the format yourself.