If anybody says the windows and doors are maintenance free then most probably they do not know the industry well.
Here are a few guidelines for keeping your windows in tip top shape
Frames – wash with hot soapy water together then again with a PVCu cleaner you could buy from the sheds – try not to use abrasive cleaners as this will scratch the frame
Gearing – the sliding bolt method of locking ( called an espagnolette ) is always the achilles heel of any window or door – these need to be lubricated with oil ( not WD40 ) every 6 months – we always say when the clocks change – this will stop them seizing up - as rule if it moves oil it.
The same applies to PVCu front doors – also put a bit of oil on the key to lubricate the inside of the cylinder
When oiling a door always put a rag on the floor to catch the drips