How long does latex last?

i was going to buy this a href="http://www.amazon.com/gp/product/B004JKP34K/ref=ox_sc_act_title_3?ie=UTF8&m=A3JHUUPV3ODEZ3" rel="nofollow"http://www.amazon.com/gp/product/B004JKP…/a because i need some rubber tubing.but it will probly take me a while to use it all.i know rubber gets hard and starts to crack when its old so would i have that problem with this tubing?how long would it take for this tubing to harden?is there a way to keep it from hardening or to make it soft after hardening?