You need to replace the filter cartridge of the Philips AWP1775CH after 12 months of use, or if the volume of purified water decreases substantially, or if the filtered water still has an unpleasant smell or is still turbid after purification.
That's very good enough. My connection is 7cm from the wall and I still have about 3cm between the filter and the wall.
I would say at least 4-4.5cm should be enough.