Some creative people can live nicely off the passive income they earn from royalties from their works. And that’s just one way to help fund a comfortable retirement.

But what chance does an artistically talentless nerd like me have? A good one, I think. And it’s all because I invest in FTSE 100 shares.

It helps to start as early as possible in life, and put away as much as we can each month. But how much, and how long we need to do it, depends on a few things. My two key ones are what kind of income I think I’ll need, and what annual returns I might be able to manage.

Long-term returns

Over the past 20 years, the average FTSE 100 return has come in at 6.9% annually. So, as my example today, I’ll use one of my long-time favourite dividend stocks, Aviva (LSE: AV.). I choose it because it has a forecast dividend yield of… 6.9%.

That’s not guaranteed, as dividends never can be. And I’m not thinking about any share price appreciation. If it can make 2% a year on top, I can think of that as an inflation adjustment.

In reality, I’d never put everything into one stock. I’d spread my money across different dividend stocks in different sectors for some diversification. And I hope to be able to match that historical 6.9%.

I think Aviva is a fair example for me to use. Individual investors have to set their aims in line with their own needs and with how much risk they’re comfortable with.

How much do I need?

What other income, from pensions, for example, do we have? How expensive is our lifestyle, and the cost of living where we live? They can all influence what we need to achieve.

If I wanted to target a passive income of £20,000 from an annual 6.9% return, I’d need to build up a pot of around £290,000. And that could look like a pretty daunting amount.

But if I could put £1,000 a month into Aviva (and it maintains its 6.9% very year), I could get there in 15 years. And even if I could manage a more modest £500 a month, I could still reach my goal in 22 years.

Or if I only wanted £10,000 a year to add to whatever other income I have, I’d need to set a £145,000 goal. On the same basis, I could hit that in just nine years at £1,000 per month. Or stretch it to 15 years at £500 each month.

Picking stocks

Aviva itself, though one of my favourites, is in the financial sector. And we’ve seen how tough that can be. In any shaky economic times, I’d expect financials like banks and insurance firms to suffer.

And though the Aviva share price has done well in 2024, I still see volatility ahead.

But with diversification, I think it can help me to match those long-term FTSE 100 returns. Or maybe even beat them.