CT scan shows there's still lots of toner left in an “empty” cartridge
Somewhat related, I recently bought a Brita water filter jug which has a little led on the lid which glows red when the disposable filter cartridge has “expired” and needs replacing.<p>Before I even started to use the thing I knew what to expect. Sure enough it starts to glow red after a ridiculously short period of time of using a brand new filter cartridge.<p>I’ve been ignoring it for a few weeks now and checking for any difference in taste of the filtered water but haven’t detected anything yet. I’d recently been wondering about how to verify the filter’s effectiveness somehow as I’m sure this indicator is less than useless and essentially setup to “lie” for profit.<p>There should be laws against this sort of thing. Any indicator that tells you when a consumable needs to be replaced should have to meet some level of accuracy in order to be legal.