On paper, buy-to-let looks simple. Find a good property, rent it out, and watch the income roll in. In reality, so many investors see their yields chipped away because they fall into traps that could have been avoided.

The first and most common mistake is forgetting about the hidden costs. It is not just the mortgage. Service charges, ground rent, insurance, repairs and unexpected maintenance all eat into profit. A new boiler or a leaking roof can wipe out months of rental income in one go.

The second pitfall is ignoring void periods. Even in strong markets, there will be gaps between tenants. A single month without rent can slash annual returns by almost ten percent. Properties in high-demand areas, close to universities or transport links, are far less likely to sit empty, so location really does matter.

Then there is tenant management. Chasing rent arrears or dealing with property damage is time-consuming and expensive. Skipping thorough checks or trying to save money on management can end up costing far more in the long run. Reliable tenants are the foundation of reliable yields.

Finally, many investors take their eyes off the bigger picture. Regulations are changing, especially around energy performance and rental standards. A flat that looks profitable today may need costly upgrades tomorrow just to stay compliant. Those who do not plan ahead risk being caught off guard.

The truth is that yields are fragile. They are easily eroded by small oversights and bigger surprises. Smart investors are realistic about costs, prepared for the occasional empty month, and alert to the shifting demands of both tenants and regulators. Protecting yield is not about luck. It is about diligence, foresight and avoiding the obvious mistakes that continue to trip others up.