6 Investing Mistakes You Need To Avoid

You are having a great week. Work is going well, the sun is out, life is good. Then you open your investing app and your mood tanks because your portfolio is down 2%. Two minutes ago you were fine. Now you are anxious, wondering whether you should sell everything and stick with a savings account.

If that sounds familiar, you are not alone. That reaction is one of the biggest reasons why most investors underperform the market over the long term. Here are six mistakes you should avoid if you want to become a better investor.

1. Checking Your Portfolio Every Day

This is probably the most common mistake. When you have money in the market, it is tempting to check how it is doing every hour. But there is a real psychological cost to that habit.

Daniel Kahneman, who won the Nobel Prize for his research on decision-making, showed that we feel losses roughly twice as strongly as equivalent gains. If your portfolio goes up by 2%, you feel a little happy. If it drops by 2%, you feel twice as bad. The emotions are simply not equal.

Now think about what happens when you check your portfolio every day. On any given day, the market is roughly a coin flip. It goes up about 53% of the time and goes down about 47% of the time. So nearly half the time you look, you are going to feel the sting of a loss, even though these daily movements mean absolutely nothing for long-term wealth creation.

There is a famous finding by Fidelity that looked at which clients had the best-performing portfolios. You would expect it to be the most active traders, the ones constantly researching and optimising. But it was actually the opposite. The best performers were accounts that had not been touched in years. Some belonged to people who had forgotten about their accounts entirely, and some had even passed away.

The lesson is simple. The less you tinker, the better you tend to do. Set up your investment account, automate your contributions, and then step away. Check it once a month if you want, but daily checking is just hurting you.

2. Ignoring the Fees

This one is sneaky because fees do not feel like a big deal when you see them as a small percentage. But when they compound against you year after year over a 20 or 30 year investing horizon, they eat a massive chunk of your returns.

It is not just the obvious fees like platform charges or fund management fees. You also need to pay attention to foreign exchange fees when buying US stocks from a European account. And then there are spreads, which most beginners never think about.

What is a spread?

Say a stock has a market price of around 100 euros. When you go to buy it from your broker, you do not actually pay 100 euros. You pay the ask price, which might be 101 euros. And if you were to sell it at the same moment, you would get the bid price, which might be around 99 euros. That 2 euro gap between the buy and sell price is the spread. The moment you buy, you are already down 1% before the stock has even moved.

Some brokers have much wider spreads than others, and that adds up every single time you make a trade.

Same money in, same investments, completely different outcome. Take the time to compare brokers and look at the full picture: platform fees, fund fees, FX fees, and spreads. It is one of the very few things you can actually control as an investor.

3. Waiting Until You Have "Enough" Money

One of the biggest myths about investing is that you need thousands of euros to get started. That might have been true 20 years ago, but today many brokers let you buy fractional shares from as little as 1 euro. You can own a piece of companies like Amazon, Microsoft, or an S&P 500 ETF without needing hundreds or thousands of euros for a single share.

Small amounts genuinely add up over time. If you invested just 50 euros a month starting at age 25 with an average return of 8% per year, by the time you reach 65, you would have over 170,000 euros. The majority of that, around 146,000 euros, comes from compound growth rather than the money you actually put in.

The biggest advantage you have as a young investor is not money. It is time. The worst thing you can do is wait until you have "enough" because that day might never come. Start small, stay consistent, and let compounding do the heavy lifting.

4. Listening to Doom Content

On March 9, 2009, the S&P 500 hit its lowest point during the financial crisis. If you picked up the Wall Street Journal that morning, you would have seen the headline: "How low can stocks go?" Reuters was running stories about banking fears and deeper recessions ahead.

That day turned out to be the absolute bottom. From that point, the market went on one of the longest bull runs in history. The S&P 500 grew from around 676 points to over 6,000 points. Nearly a 10x return. If you had listened to the news and stayed out of the market, you would have missed all of it.

We now live in a world of 24/7 financial content. YouTube, X, TikTok. The algorithm rewards fear. A thumbnail saying "crash is coming" gets 10 times more clicks than one saying "markets look fine, keep investing." There is an entire ecosystem of creators who produce doom content every single day because it works for them. You click on it because you are afraid you might miss something important.

But their incentives are not the same as yours. You want to build long-term wealth. They want views. Being informed is fine, but changing your strategy every time someone on the internet says the sky is falling is not.

5. Not Diversifying Your Investments

This one feels obvious, but you would be surprised how many people think they are diversified when they are really not. If your entire portfolio is an S&P 500 ETF, you are essentially 100% in US large-cap stocks with a heavy lean towards technology. Companies like Apple, Microsoft, Nvidia, and Amazon make up a massive part of that index.

US tech has had an incredible run, but concentrating everything in one country and one sector is a risk no matter how well it has performed recently.

True diversification means spreading your investments across different asset classes and regions. That could include:

• European and emerging market stocks
• Real estate through REITs or physical property
• P2P lending for alternative income
• Gold as a hedge
• A small allocation to Bitcoin if you are comfortable with volatility
• Cash as a buffer

The point is not to chase returns in every category. It is to protect yourself when one area of the market is not doing well. If US tech has a rough year, having exposure to other assets means your entire wealth does not take the same hit. You do not need 30 different holdings, but owning more than just one ETF tracking one index in one country is certainly worth thinking about.

6. Comparing Yourself to Others

This is the mistake nobody really talks about, but it might matter the most. Social media has made it incredibly easy to compare your financial journey to everyone else. You see someone on Reddit posting their half-million portfolio at age 30, or a YouTuber showing their monthly dividend income, and suddenly your 200 euros a month feels pointless.

But here is what you do not see. You do not see the inheritance they may have received. You do not see the six-figure salary. You do not see the years of living at home rent-free. Everyone's starting point is different, and comparing your chapter 1 to someone else's chapter 20 is a guaranteed way to feel terrible about yourself.

The only comparison that really matters is you versus you from last year. Are you investing more consistently? Have you reduced your fees? Are you more disciplined than you were six months ago? That is what actually counts.

100 euros a month invested consistently beats 1,000 euros a month invested randomly whenever you feel like it. Your journey is your own, and the fact that you are even thinking about this already puts you ahead of most people.

The Bottom Line

None of these mistakes are complicated to fix, and that is kind of the point. The best investing strategies rarely are. Automate your contributions, keep fees low, diversify properly, ignore the noise, and focus on your own progress rather than someone else's highlight reel.