In Ašič's notes the time of gathering recurs more often than almost anything else. For every plant he gave which part and when, and both had a practical reason.
In the morning, once the dew has dried and before the sun beats down. A wet plant heats up in the bunch and turns brown, and one that is too hot loses part of its volatile substances before it gets home.
Flowers are gathered just as they open. Leaves before flowering, while the plant has not yet put everything into the flower. Roots in spring before it shoots, or in autumn when it returns to the ground, when there is the most in them.
We gather away from roads, fields and the paths that dogs walk. This is not an aesthetic matter.
And we gather only what we recognise with certainty. Doubt is the answer: leave the plant in peace.
This answer is general in nature and does not replace a visit to the doctor. The products are foods or cosmetic products and do not replace medical treatment.