Park a few months of real bills in cash before you buy a single share. If a broken boiler can force you to sell, you do not have an investment. You have a loan from next week's panic.
The market will have a tantrum. That is its job. Your job is to not be the person who has to sell because the washing machine died in the same week.
An emergency fund is not an investment. It is a moat. A few months of real expenses (rent, food, the boring baseline, not the holiday version of your life) sitting in cash or the nearest thing to it. It earns almost nothing and that is the point. It is there so the hoard never has to be.
I have already paid for mixing the two piles. In September the broker flagged the account for a KYC review right after a deposit landed, and restricted it. The buy that cleared is in the ledger. Everything after that sat still. No new deposits. No "just this once" top-up. If that cash had been the boiler money, I would have been selling the thing that pays me, in a week I did not choose. The yield would not have failed. I would have.
Growth investors get the same bill, and a worse version of the same day: forced selling in a bad month turns a paper drawdown into a realised one, and takes the compounding with it. Nobody is exempt from boilers. Nobody is exempt from a broker that says wait.
Two piles, two jobs
How many months is the same question as the one in Growth or dividends? Match the portfolio to your paycheque, asked earlier. If your income is a salary that lands on the same day every month from an employer that is not going anywhere, the cushion is covering bad luck. If your income is lumpy (self-employed, commission, seasonal), the cushion is covering bad luck and a thin quarter, and it has to be bigger. That is the whole rule.
Three months is a common rule of thumb, six if your work is lumpy, and neither of those is me setting your number. Write the real monthly nut down. Be honest about it. The number that lets you sleep is the right one, and it is almost always bigger than the number that looks tidy in a notes app.
Where it lives: somewhere boring. An easy-access account. Not a stock. Not a fund. Not the same pile you are about to start investing with, whatever you decided to put in it. If you have to log into a broker to pay the dentist, it is not a cushion. It is a temptation with a quote attached. And sometimes, as of September, it is a temptation you cannot even reach.
The goblin lives in Thailand and still keeps this pile. Geography does not cancel boilers. It does not cancel visa fees, a flight home, a laptop that dies the week before a tax return. The details change. The shape does not: cash first, then the first buy.
People skip this step because it feels like doing nothing. Sitting on cash while a mate is already "in the market" feels like losing. It is not. It is refusing to build a machine you will have to smash the first time life happens. Life happens. The internet is very quiet about that bit.
The portfolio is not the cushion
Here is a real payment, so the two piles stop being a metaphor. Select Monthly Income Fund paid 0.50p per share in September 2026. I owned 100,000 shares. £500 landed. That cash is investment income. It is not the emergency fund. It does not sit there for the boiler. It goes in the ledger the day it lands, and the cushion is a different line, on purpose. If your lane pays you nothing while you hold it, the line is even clearer: there is no cash coming out, so the cushion is the only thing standing between a bad week and a forced sale.
If you spend the cushion, you rebuild the cushion. You do not "just this once" nick it from the hoard because the hoard is up this month. The hoard is up this month until it is not. Forced selling is how a boring plan turns into a story about bad luck, and it was not luck.
A first buy made with money you might need in three months is not a first buy. It is a loan from a future problem. Wait. The market will still be open. The coupon question from Does it even pay a coupon? still applies. None of it matters if a bill can bounce you out of the position.
Not financial advice. Just the order one goblin wishes he had treated as a rule rather than a vibe.
When the cushion is actually there (counted, parked, boring) the next job is the small first buy, in whichever lane you picked. The goblin's version of that first buy is the first hundred of boring yield. The sizing rule in it works the same if what you bought was a tracker.