Analysis of actual market rental rates
The first thing to do is not to panic and not to agree immediately. Always check the current average rental rate on the market for similar premises. Sometimes the landlord is simply testing whether you are willing to pay more; they want to make money too. In reality, the increase may be exaggerated, and you will have a strong argument for negotiation. If you find information that neighbouring properties are cheaper, this is good leverage. The opposite situation is also possible: if it turns out that your contract is already favourable, it will become clear that the landlord's demand is quite fair.
Arguments for negotiation
After the analysis, it's time to talk. Be calm but confident. Remind the landlord that you are a stable and reliable tenant, pay on time and don't cause any problems. Losing such a tenant is also a risk. Make it clear that a sharp increase could lead to the termination of the contract, and finding a new tenant always takes time. The main thing in negotiations is to hint that your departure will be no less painful for them than the increase is for you. Back up your arguments with figures and facts.
Alternatives
In any situation, it is better to have a plan B, advise MAFPELS managers. Even if you want to stay, start looking for other options. This will give you confidence in negotiations. Maybe you can find something better for the same money. Sometimes, just knowing that you have an alternative makes it easier to talk to your landlord. It is possible that competition will make them more accommodating. And if you do find a better option, you will have real freedom of choice.