Read your drivers manual, the information you are looking for will be in there.
You change it according to the manufactures recommendations which will be at a certain mileage.
It depends which engine is fitted. The 1.4/1.6 petrol engines require removal of the cambelt cover and cam belt to gain access to the thermostat. This in my opinion is not a job to be tackled lightly. One mistake replacing the belt could mean a trashed engine!!!! The 1.8 petrol engine is quite a bit easier as the thermostat housing pokes out from the side of the cambelt cover. Sorry, don't know about the 2.2 petrol or the diesels.
You know the heater hose on a vehicle needs replacing when it beings to swell and soften. The heater hose runs from the intake manifold to the heater core.
It should be changed every 60,000 miles. I am not sure if it is an interference engine or not.
If its leaking or has been bent or crushed it needs replacing.
You won't know it needs replacing - it fails catastrophically, without any symptoms. Factory recommended replacement mileage is 95,000 miles. If you have passed that mileage you are living on borrowed time.
Take it off and take it to a good auto parts store for testing.
It needs replacing every 60,000 miles.
If it is leaking it needs replacing. If you have no heat and the inlet heater hose is hot and the outlet is cool, it is stopped up and may need replacing, if it cannot be flushed out.
It would help to know the sensor that needs resetting.
Before replacing all your cookware make sure you know what your specific needs are. Also, try to find something with a lifetime warranty.
easiest way to check pcv is to pull it out of where it is and shake it if it rattles, it is good. if it does not rattle it is clogged up and needs replacing