In spite the fact that a thatched roof can last 60-70 years, it needs to be regularly watched and it may need some mending at times. 
The main reason why the state of the roof might worsen is moisture in the upper layers of the roof. In moist and warm conditions the microbiological process gets activated and it causes the reed to become brittle. The sharper the angle of the roof, the less amount of moisture gets absorbed through the surface and the lifetime of the roof lengthens.
Repairs of your roof should be planned for the driest season. Even a large piece of plastic should be at hand so that openings could be covered in case it begins to rain.
Repairs are to be started with finding out the most severely damaged areas and removing the spoiled layers. If there are protruding details on the roof – these places call for special care as in many occasions these spots turn up to be the weakest
