I spent 7 years building my son an ETF portfolio. Here's what I told him when I handed it over.

My son turned 18 last month. Seven years ago I started building an ETF portfolio on his behalf — pocket money, birthday cash, part-time job earnings. Now it's his. I wrote him a letter. Sharing it here in case it's useful to anyone else's kids, or anyone who wishes they'd had a version of this earlier.

Dear son,

Time flies. My little boy is no longer little — he's a full-grown man of 18.

I'm older now, which means I've lived through 2000, 2008, and 2020 as an investor. I want you to start with a financial map I never received. There are tools, frameworks, and choices available to you that took me years to discover.

I'm trying to give you something many people only find in their 40s or 50s: time. With FIRE, starting age is often more powerful than return optimisation.

I hope I've given you two gifts — the capital itself, and understanding. What an ETF is. Risk versus return. Whether to keep cash in a high-interest savings account (some of it, yes — your emergency fund). These things matter before the fancy stuff does.

Ask questions. About stocks, allocations, scams, dangerous instruments like Contracts For Difference, whether you should short an OpenAI IPO (please no — walk before you run). The only dumb question is the one you don't ask.

Have an attitude of gratitude. For me, growing up in Newcastle, UK, the narrative was simple: school, work, buy a house, pay it off, retire. Investing wasn't discussed. I'm genuinely fortunate to have built a life in Australia — a country with a real investment culture — and to have had enough breathing room to even consider this path. Not everyone does. Never lose sight of that.

Investing is fascinating, but it sits on top of a foundation: stable income, surplus cashflow, financial literacy, and time to think beyond immediate survival. Get those right first.

Son, this is a toolkit, not a doctrine. There is no perfect portfolio. A portfolio is trying to solve multiple problems at once — return, volatility, tax, simplicity, behavioural fit, the sleep-at-night factor, time horizon, life goals. Optimising one dimension often worsens another. Don't let perfect get in the way of good enough.

Don't beat yourself up when investments don't go to plan. You made the best decision with the information you had. Hindsight is a ruthless and unfair judge.

Yes, some people time markets correctly. The hard part is doing it repeatedly, reliably, across cycles, with real money, after costs, without hindsight. Almost nobody manages it.

And avoid the temptation to fiddle. Financial media will always give you a reason to sell, buy, or chase the hot new thing. Fiddling feels productive. Compounding is maddeningly boring by comparison — for long stretches, successful investing looks almost disappointingly uneventful. Then you look back years later and think: goodness, that became ten times larger. Sometimes the right move is not dramatic action. It's maintain, monitor, and resist unnecessary intervention.

I've positioned you for launch. I helped build the runway, explained the instruments, and left the tower frequency open. I can't pilot your entire flight plan — and I wouldn't want to. Your journey will be very different to mine.

Bon voyage.