I'd say the unfiltered water quality still might matter in your case. I had to swap to the "stronger" orange marked Maxtra cartridges for harder water because the standard ones weren't actually helping. And I can tell the difference because our kettle gets less limescale now - that's also still the marker for me when filter is about to wear off. For our family one cartridge lasts for about a month now.

I'm using these jugs for 10 years already and the quality of these dropped significantly. The older Elemaris line (with "probes") had more durable plastic while the newer Style (with silicone lid handle) already broke twice during washing. At leas the rounded sensor is more waterproof than the "probe" - that one I had to replace twice and luckily the local distributor send these for free.