Door that stick can have many different symptoms and causes and therefore need different remedies too.
Sometimes it is a case of one or more of the hinges becoming loose, it could be the screws, the pin or both.
More often than not the door in question is fine until humidity causes it to stick, I don't know how many times I have heard "it only sticks when it rains?".
Other causes of the door not closing properly or at all can be structural and in these cases I find that the more room I give for the door to close the more the frame shifts so these symptoms, (usually accompanied by large cracks at the top of the architraves) should be a concern and further investigation of the drainage of the site and foundation should be carried out.
When hanging a new door it is important to allow 5mm clearance all the way around the door for expansion during humid weather and a couple of layers of paint.