Chemicals and reagents often come in many sizes and volumes.
And sometimes you get a lot more grams or milliliters per dollar if you go for the larger size!
And that's of course great if you know that you will be able to use it. But it really isn't great when it turns out that the larger size simply was too much for you to use before the expiration date.
So stick to the plan: resist the temptation and order what you need!
That's good for the planet & the environment -- and you don´t have to deal with the disposal of expired reagents.
And if you should stumble upon reagents in your lab that you know you won't be able to use before it expires: give it away! Send an email around the institute and ask if others will be able to use it.
That's a really nice thing to do -- and who knows: maybe you will get to know a new colleague or resource this way?