Increase in rent can be a big headache for any tenant and specially students as there is no money inflow. Any person who has rented a place ever knows this pain and can tell you increased rent just disturbs all the budget. Rent increases can be because of many reasons like increased cost of services, appreciation in the rate of property, inflation which is one of the most common reasons and many others.
Sometimes the rent increase can be as part of a pre-agreement made with the landlord or agent. Such increases are decided based upon how the prices will increase of house and property related services in the near future. So the landlord may wish to add an escalation factor in there which is generally justifiable. Make sure to look for this in your tenancy agreement and get all the clarifications related to this. You can also ask for justification on the same. A simple way to understand would be to see the locality in which the property is located and how its status is going to change.
Another way to increase the rent could be in between your tenancy period. Do note that the landlord has to seek your permission for doing this and also inform you the reason. You can negotiate the increase by either asking him or her to not increase it beyond a certain level or else provide some extra facilities in lieu of the increased amount.
In case you are not happy with the increase you can look for some decrease in the services provided by the landlord. But do make sure you do not compromise on the basic requirements. The best way to deal with these situations is to have everything cleared from the start itself. A clear tenancy agreement should state the rent and how and when it can be increased. If your agreement mentions that the rent is static and cannot be changed, then you may choose to approach the tribunal wherein you will be required to prove your problem with sufficient proof.
At the end of the day, your good reputation with the landlord matters a lot. Try to have a good relation with them and as well as the agent. Agent is who will help you when you will be looking for a new property. Any problems that you are facing related to the current property should be discussed with these two only.