Hi photog72,
Most of the members of the site don’t have a discount code and you just need to call and let them know that you are a member of the forum here before you place your order.
While there is no way to quantify how long any particular mattress will last for any particular person because it will depend on many variables … if a mattress isn’t on the edge of being too soft for someone when it’s new and it doesn’t have any lower quality materials or components or weak links in the design relative to their body type then for most people it would be reasonable to expect that it will maintain a suitable level of comfort/support for 7 - 10 years. Depending on the type and quality of the materials some mattresses can last considerably longer (and it could be considerably less if there is a weak link in the mattress). There is more about the “minimum” specs I would suggest and the durability and useful life of a mattress relative to different people in post #4 here and the posts it links to.
Phoenix