I have been using it for 3 years, and even in different houses due to moving. I can confidently say that it improves the water quality by 95%, and the reason I don't say 100% is because it doesn't completely eliminate the salts. However, I have forgotten what the smell of chlorine and metallic taste are like. Particles and other traces in the water do not pass through at all. Every six months, when the flow decreases somewhat, I take it out and scrub it with a hard (plastic) mesh for dishes, rinse it with plenty of water, and it returns to its original condition. Indeed, over time, I notice changes in taste, so I replace it. Two things to note:
1. If you are away for a long time, 3+ days, when you return, let it run to empty the old water. The reduced chlorine content does not preserve the water for a long time and needs to be refreshed. That's why, in my opinion, during the summer, it should be left in the refrigerator for a maximum of 4-5 days.
2. If you need to move, remove the filter, clean it a little with wire, and the transportation should be done in water, with a container or a bag. It should not dry out to avoid damage.

Finally, I do not use a Doulton device, but Watts Water Technologies (USA), which has nothing to envy from Doulton. It is very durable and has not had any issues for such a long time, knock on wood.