The chemicals and reagents that we only use rarely are most likely to reach their expiry date and get wasted.
Instead of having several stocks of the same chemicals in one single building or floor, you can share chemical cabinets with other labs.
Alternatively, your center, building or floor can have a common document listing the chemicals and reagents that the individual labs are willing to share.
This reduces the risk of reagents being wasted -- and that´s good for the environment and the planet.
Sharing may not be suitable for the chemicals you use the most, but it´s great for chemicals with a low turnover!
Giving (and asking for) aliquots/reagents/materials for pilot experiments is also a great way to reduce waste.