TL;DR
Chests should have an output option parameterized by an item that outputs the lowest time to spoil of any item of that type in their inventory.What?
Chests allow you to output their inventory. There should be another checkbox that lets you output a "ticks to spoil" timer on a particular signal for a particular item in their inventory. This should be though all items of that type in the chest's inventory and output the smallest value for "ticks to spoil" of any such item.Why?
It would be very helpful to be able to toss some items that are about to spoil in the fire before they spoil. Eggs of various kinds of particular. A filter that grabs "the most spoiled item" is insufficient as that item may actually be pretty fresh.This doesn't solve the problem for all places where a spoiling item could be, such as in a crafting or output slot, and that's OK. Just solving it for containers would be a major step forward.
Soil percentage could work, but then the thresholds would have to be different for different items based on how long it is before they spoil. It's also imprecise. So I think a plain accounting of "time until spoil" is more helpful. The natural unit for this is ticks.
If a percentage measure is strongly preferred, I would ask for a measure in tenths of a percent instead for more precision.
I hunted for another suggestion like this, and didn't find it. I'm glad you did.