Five units to fifteen: the four things that break

Published 16 August 2026 · Written by the Lar founder

Something changes when a Scottish landlord grows from five rental units to fifteen.

We have watched it happen again and again while building Lar. The same four things break, usually in the same order.

1. Compliance tracking moves from memory to probability

At five units, you have roughly 30 to 45 certificates and registrations to keep track of. Gas safety every year. EICR every five years. EPC every ten. Landlord registration every three. Smoke and heat alarms, legionella assessments, deposit protection.

At five units, you can hold most of that in your head, or in a spreadsheet tab you check every so often.

At fifteen units, the same list runs to 90 to 135 obligations, all on overlapping cycles. Missing at least one in a given year stops being unlikely and becomes close to certain. Nobody is being careless. There are simply too many dates for one person to hold.

And one missed gas safety certificate is enough to invalidate your insurance, undermine the tenancy and leave you facing criminal liability. The nine certificates guide covers what each obligation involves.

2. Your entity structure fragments your financial picture

Most Scottish landlords start out owning everything in their personal name. By fifteen units, that has almost always changed. Two SPVs, a personal holding, maybe a partnership. Section 24 pushed most higher-rate taxpayers down this road.

The problem is that a spreadsheet built for one owner does not split neatly across three. Income, expenses, mortgages and tax all need tracking by owner, because that is how they are taxed and that is how your accountant needs them.

At five units in one name, that is one tab. At fifteen units across three owners, it is a tangle that most landlords do not sort out until tax season forces them to.

3. Cash flow becomes unintuitive

At five units, you can hold the monthly position in your head. Rent comes in, mortgages go out, and what is left is roughly predictable.

At fifteen, the surprises start landing together. A void period overlaps with a boiler replacement. Two mortgage payments and an insurance renewal hit in the same week. Since April 2026, a quarterly MTD deadline sits on top.

No single one of these is unmanageable. The problem is that fifteen units produce enough of them at once that “I roughly know where I stand” stops being true.

4. The coordination load hits a threshold

At five units, tenant queries, contractor bookings and accountant emails fit around the rest of your life. At fifteen, the messages, maintenance requests, certificate renewals, reference checks and money questions add up to a job in their own right.

That is the point where most Scottish landlords face a choice. Hand the whole thing to a letting agent and give up 8% to 12% of the rent, or build a proper system for the work they are already doing by hand.

Most landlords we have spoken to at this scale chose neither for longer than they should have. They stayed in the gap, running the portfolio on effort and memory, until something fell through.

Closing the gap

That gap is the specific problem Lar is built to close. It keeps compliance, the numbers, mortgages and tenancies in one place, works out what needs your attention and helps you deal with it, without hiring staff or handing over to an agent.

Growing past fifteen? The companion guide on what breaks between thirty and sixty units covers the next threshold.