[ska]

> Any indicator that tells you when a consumable needs

I'm not a fan of the blinking reminders either, but it's not a monitor it's just a flashing version of the "remind me in the months" wheel or whatever.

The problem they face is a hard one. There are really two timelines you care about, one is how long it stays effective, the second is how long it is safe.

The first one especially is highly affected by both usage patterns and the water quality you are starting with. With an inline system I'd sort of hope to have reasonable monitoring, but Brita filters are fundamentally passive devices, to do this "properly" your going to 10x-100x your costs, maybe worse.

A less cynical (than pure profit motive) take on the timing would be that the lifteimes are all based on some sort of average case for usage and (bad?) test case for hardness and water quality. I suspect they have to be careful in what they say about how best to adjust this without opening themselves up to liability, so they don't.

[lancesells]

Instead of a timer you could have a counter. The Brita filter looks to last 40 gallons. My Brita pitcher holds 10 cups. 10 cups equals 0.625 gallons. Which means my filter lasts for ~64 fills of the pitcher.

So using a counter until 64 would tell me to refill. All you need is a plus sign and some way to reset.

Now that I've done the math I might start writing this on a pad next to my refrigerator because I never have any idea when to switch the filter. Paper is preferable to electronics in my life.

[bewaretheirs]

At one point Brita distributed a spring-driven mechanical ratchet counter that would sit on top of the filter cartridge; it had some sort of diaphragm arrangement that would sense the water level and "tick" once per refill cycle and tell you when it was time to swap in a new filter.

[ska]

I wonder why they go rid of it. Was this shipped with every filter or was it a think you reset and put on again? Do you recall if it could tell the difference between a partial fill and full fill?

What you really want is to measure the volume through the filter, but I can't think of a way to do that cheaply and mechanical only.

[bewaretheirs]

It was reusable. You would turn it back to the start to reset it when you'd pull it off the top of the old filter and stick it on top of the new one.

I don't recall whether it came with the pitcher or as a bonus item included in a filter-multipack. It just counted one "tick" on a ratchet per fill/empty cycle, no attempt to measure volume or fractional fills.

[lozenge]

They probably consider the electronic version more "modern". Even though it contains a non replaceable, non rechargeable battery.

[ska]

That definitely works better than a timer, but still has to be adjusted for the water quality in your house.

But it also assumes you go fill-to-empty. In my limited experience they are often refilled from partially empty, whenever convenient. If you are doing this on paper, maybe you should count output instead of input? More work though.

[lancesells]

Didn't think of water quality. I'll have to see if I can test it. I live in Brooklyn in a superfund site so it'll be interesting to see.

[ocean2]

One may attempt to sterilize the used filter. For example by using a microwave. This could prolong the lifetime of the filter cartridge.

[ska]

That could help on the biofilm/mold front, but won't do anything about particulates in the filter.

[tailspin2019]

Yes in fairness you make some good points.

But given what we see the printer industry blatantly doing - I’m still cynical!

[ComodoHacker]

Ironically, the printer industry is getting off with less scrutiny from regulators because safety isn't involved.