Fund group Fidelity International is the latest to publish figures comparing the returns you would have made if you had invested your money rather than deposited it in a high street savings account.

The firm looked back over 30 years and found a deposit of £10,000 in the average UK savings account back in 1986 would now be worth £28,198 in the bank. If that same money had been invested in a FTSE All Share tracker fund over the same time period, the £10,000 would be worth £121,466.

If the same investor had put their £10,000 in a FTSE 100 tracker, they’d be sitting on £126,867 after 30 years and in a FTSE 250 tracker, the portfolio would be worth £265,035.

“If anyone is unsure about the benefits of investing in the stock market over stashing cash under the mattress, especially over the long term, then our calculations highlight just how rewarding investing can be,” said Fidelity’s Tom Stevenson.

Stevenson is right. These returns are impressive, particularly considering the average easy access savings account is paying a paltry 0.58% at the moment.

However, it’s worth remembering stock market investing isn’t for everyone. Yes, rewards are possible, but not guaranteed.

If you’re thinking of stepping into the world of investing, here are a few questions to consider before you make your move.

When do you need your money?

If you decide to invest in the stock market, you need to be comfortable locking your money away for the long term. Remember, the example above describes a 30-year period. If you’re looking to access your money in the next year or two, you may be disappointed and could in fact end up with less than you started with.

The power of long term investing comes from compounding, which is reinvesting the income you receive from your investments, thereby increasing the amount of money working for you over the longer term. In simple terms, it’s converting income into capital to earn more income and so on.

What do you need the money for?

If you need your money back to pay for something specific, such as university fees or a house deposit, and need a guaranteed minimum amount, stock market investing isn’t a fail-safe option.

You don’t want to be forced into a situation where you have to pull your money out too early, or at the wrong time, i.e. when the market has tanked.

The saying goes ‘time in the market is more important than timing the market’. To avoid buying at the peak or selling when the market is low, experts suggest investing regularly, on a monthly basis for example, rather than putting in a lump sum.

Are you comfortable with losses?

Markets go up and down by their very nature. If you buy shares, you need to be prepared for volatility. If you’re invested for the long-term (Fidelity says 30 years is a “realistic investing timescale for many people”), there will be periods when the value of your portfolio plummets. Panic selling at this point would be the worst thing to do. Although market dips can be unsettling, you need to become adept at detaching from market noise.

Do you have time to monitor your portfolio?

Investing means more than just sticking a lump sum of money into a portfolio of shares or funds. You need to review your portfolio at least twice a year. If you fiddle about more regularly than that you risk reacting to short term noise which can build up trading costs and chip away at the value of your portfolio. However, ignoring it altogether could be dangerous.

“Market movements could mean your portfolio no longer matches your risk appetite, time horizon or goals and your asset allocation may need reviewing or rebalancing,” says Stevenson.

You also need time to do your research. Are you prepared to read up on markets or what a fund does and how it generates returns? You should never invest in something you don’t understand, so if you are time poor, you might be better off outsourcing the decision making to an intermediary, but that will incur another layer of costs.