I date chemicals both when I receive them and when they are opened, then also note on the bottle when they’ve been used. I also weight them, including the container, when they come in and note that on the bottle - so when doing the yearly inventory I can just subtract what’s left from that initial number.
This is kinda a rough overview of the tasks I do, I guess? It changes a lot, depending on what’s happening in the department and the wider school:
