I’d say for twice the expected usage time of the original packaging.
Say on average someone goes through the original bottle once a month (yes that is way too much usage, just as a hypothetical), they should be required to have it prominently displayed on the new label that the new size is estimated to last x% less time(or more time) than the previous packaging, for 2 months minimum.
I’m cases of recipe changes I think it should be required to have that on the packaging as well.
I could see a soap mfg just diluting the soap to meet the volume, and bypass the requirement.
I’d say for twice the expected usage time of the original packaging.
Say on average someone goes through the original bottle once a month (yes that is way too much usage, just as a hypothetical), they should be required to have it prominently displayed on the new label that the new size is estimated to last x% less time(or more time) than the previous packaging, for 2 months minimum.
I’m cases of recipe changes I think it should be required to have that on the packaging as well. I could see a soap mfg just diluting the soap to meet the volume, and bypass the requirement.