I’m slowly putting together a DIY mattress and have received my pocket coils. Will it hurt anything if I leave it compressed in the box? I’ve read that foam mattresses need to be opened within a couple of months from manufacture, but wasn’t sure if the same applied for pocket coils. Thanks
Hi talisman311.
Welcome to our Mattress Forum. 
I hope you find The Mattress Underground to be a great resource in your DIY journey!
You are correct that foam mattresses would need to be opened within a fairly short window upon arriving from the manufacturer. Foams that are compressed for longer than 30 days or so in shipping and storage can reduce the durability of the materials.
Springs on the other hand are manufactured to maintain their function under stress with minimal fatigue, Car springs, for example, can hold the entire car’s weight for decades with very little fatigue or Creep (deformation) under the influence of persistent stress. Assuming that the spring unit is not compressed past the steel’s Yield strength and stored in extreme temperature conditions…if you let it sit compressed even for years, it should be absolutely fine. ( YOu can
read more in this this article
If outside elements like moisture, debris, corrosion creep in… they could play a role in the longevity of the spring. But if kept away from these elements, it’s function shouldn’t change all that much, or unnoticeable from a sleeper’s perspective.
Looking forward to updates as you move deeper into your DIY build
Phoenix