How long do chemicals last?

[fishboy13]

I have some water test kits that are about four to five years old. I was wondering if I can still use these kits or not? I'm going to be starting up a new tank soon so I have no way of currently testing them. They have been stored in a cool basement on a shelf.

Amazon.com: API SALTWATER MASTER TEST KIT: Pet Supplies@@AMEPARAM@@http://ecx.images-amazon.com/images/I/51JkLCA0LrL.@@AMEPARAM@@51JkLCA0LrL (http://www.amazon.com/gp/product/B001EUE808/)
Amazon.com: API REEF MASTER TEST KIT: Pet Supplies@@AMEPARAM@@http://ecx.images-amazon.com/images/I/61pAI8GpB2L.@@AMEPARAM@@61pAI8GpB2L (http://www.amazon.com/gp/product/B001D6Z7QW/ref=ox_sc_act_title_2?ie=UTF8&m=A1FOTJCK0ZMQ8U)

[fishboy13]

I found these expiration date times for these chemicals:
Ammonia Test Solution # 1 - 3 Years
Ammonia Test Solution # 2 - 3 Years
High Range pH Indicator Solution - 3 Years
Nitrate Test Solution # 1 - 3 Years
Nitrate Test Solution # 2 - 3 years
GH Test Solution - 3 Years
Calcium Test Solution #1 - 3 Years
Calcium Test Solution #2 - 3 Years
Phosphate Test Solution #1 - 3 Years
Phosphate Test Solution #2 - 3 Years
Copper Test Solution - 3 Years
KH Test Solution - 4 Years
Nitrite Test Solution - 4 Years

[bigbill]

i would say 1 year they start to get iffy some may last 18 months but pushing it

[MizTanks]

To me, that's a very big difference between 1-3 years. Does it all depend on how they're stored or what? I throw any and all out after a year~especially API since it's so cheap :)