Foundations

Protection or an emergency fund: which shock do you self-insure?

Quidsmith Guides · Updated 2026-07-03 · 6 min read

Game context, not financial advice. This article explains how things work inside Quidsmith, a personal-finance simulation game. The numbers are illustrative and the model is simplified for play. It is not personal financial advice. For decisions about your own money, speak to a regulated adviser.

An emergency fund and a protection policy are trying to solve the same problem: an unexpected event landing on a bad turn and forcing you to sell investments at the worst moment. They just attack it from opposite ends. One is cash you hold; the other is risk you rent out. The skill is matching each to the shocks it handles best.

Two ways to absorb a shock

A cash buffer self-insures. You hold money aside, and when a bill lands you simply pay it. There is no ongoing charge and you keep every pound you do not spend. The cost is hidden: cash left sitting as a buffer is cash not compounding in your ETF.

A policy transfers the risk. You pay a premium and, when a covered event lands, most of the bill is reimbursed. It can absorb a shock far bigger than any buffer you could realistically hold. But it is an expected loss, priced at roughly 1.4 times the average claim, it covers only specific categories, it carries an excess, and some lines lapse when you retire or sell the home.

Over a lifetime of the same shocks you pay roughly 40% more in premiums than you would pay in bills, the insurer's loading. On that measure self-insuring always looks cheaper. The catch is what the buffer costs you elsewhere.

The hidden cost of a big buffer

The premium gap above makes self-insuring look like the obvious winner, but it ignores the price of holding all that cash. A buffer sized to swallow a catastrophic late-life event is a large sum sitting out of the market for decades, quietly giving up the growth it would have earned in your ETF.

Invested (6%)Held as cash

A £20,000 buffer held as cash versus the same £20,000 invested at 6%. The growth you forgo is the true cost of self-insuring the big stuff, and it dwarfs any insurer's loading.

Frequent and small vs rare and ruinous

That is the whole decision in a sentence: self-insure the shocks you can comfortably save for, and buy cover for the ones too big to hold cash against.

Small, frequent bills are buffer territory. Insuring them just hands the insurer their 40% loading on money you could easily cover yourself.
Large, rare disasters are what protection is for. A major home or health event late in the run can be several times your buffer, and that is exactly the shock that ends games. Renting the risk out is cheaper than holding enough cash to survive it outright.
Watch the eligibility. Income cover lapses when you retire and home cover ends if you sell up, so as your circumstances change the buffer has to take back the shocks the policy no longer covers.

In the game

Most winning runs use both, in layers. A modest cash buffer soaks up the routine knocks and lets you pocket the loading you would otherwise pay to insure them. A targeted policy or two caps the tail: the once-in-a-lifetime bill that no sensible buffer could hold. Insure the disasters, self-insure the annoyances, and keep the rest of your money working.