Sugar will last for up to 2 years in the pantry or on the counter once opened before it goes bad and gets hard.
Unopened sugar will last for up to 4 years before it gets hard but the sugar does not actually spoil as in the older it gets it won't make you sick if you use it.
You can still break the hardened sugar up and use it even years later after it's became hard.
Sugar does not go bad and can be used for years.
However while sugar does not go bad it can get hard the longer it's kept and if there's high humidity where the sugar is kept then it can clump up and become hard.
However you can use a hammer or something else to break the sugar up again or put the sugar in a blender to break the hard sugar back up.
If you keep sugar stored in a sealed airtight container away from moisture and humidity the sugar should last nearly forever.
After you open a bag of sugar the granulated sugar will last for up to 2 years in the pantry before it starts to go bad.
Sugar really never spoils to the point it gets unsafe to use but the sugar can become hard and clump up but you can break the sugar apart using a meat tenderizing hammer and the sugar can then be used.
If you want to keep the sugar longer than a few months you should store it in airtight containers which also helps keep ants and other bugs out of the sugar.
Sugar can actually be keep for many years so if you want to stock up on sugar you certainly can as it never becomes unsafe to use.