There are different ways to prepare financially for retirement no matter how far away it may seem. While an obvious one may be a SIPP, an ISA can be useful too.

Using the decades before retirement to good advantage, an investor can reap the rewards of taking a long-term approach to investing.

Here, as an example, is how someone could turn a £10k ISA into one worth £132,676 over the course of 30 years.

So someone 36 or under starting today could do that before the standard retirement age of 66.

The retirement age could rise again, so it may be that even someone in their late 30s now could take a 30-year timeframe when considering this approach. (Even after 27 years though, today’s 39 year-old could still hope to have a £102,450 ISA by 66).

Doing the maths is the easy bit!

To start with, let me explain the key assumption that underpins the numbers above. They presume a compound annual growth rate of 9%.

That is net of any fees or charges imposed by the ISA provider. Those may seem small on an annual basis, but can add up dramatically over time. It definitely makes sense to shop around for the best Stocks and Shares ISA available.

That key assumption also means compounded growth of 9% a year. That can come from share price growth as well as dividends. (I presume here that dividends are compounded by reinvesting them).

But the key point in my opinion is that this growth is compounded over 30 years, potentially including some bad market periods as well as better times.

So a 9% target is harder to achieve than it may sound. I do think it is possible though.

Choosing the right shares to buy and hold is the hard bit!

Clearly then, making the right choices about how to invest is critical to success.

Diversifying across a range of blue-chip shares would be an important part of reducing the risk of one share performing poorly. £10k is ample to do that, for example, by spreading it over five to 10 different shares.

In a sense, finding the right shares could be difficult. But in fact I think the principles are simple. Basically, an investor will likely be looking for great businesses that are set to stay that way but with a share price lower than the likely long-term value.

One FTSE 100 income share to consider

As an example, one share to consider is M&G (LSE: MNG). The FTSE 100 asset manager operates in a market that has two key advantages in my view, it is huge and it is likely to be around for decades to come.

That attracts competition. Indeed, low-cost rivals like fintechs eating into the market share of long-established firms including M&G is one risk I see.

But M&G has some strengths that hopefully can help it stay competitive. It has a well-known brand. It also has an existing customer base in the millions, spread across over two dozen markets.

A mixture of institutional and retail business also provides some measure of diversification to M&G’s business. The company has proven its cash generation potential and has a generous dividend. Currently, the yield is above 9%.