Planning to upgrade from a GTX 780 to a GTX 1070 and from a i5 4670k to an i7 4770k.

My question is, how long do you think the 1070 and i7 4770k combo would last for before it goes out of date? I'm not really good at telling how long a product would last for before it starts to go obsolete/legacy.

If you guys have any other combinations i could choose from instead of mine then I'm be happy to take suggestions as long as the CPU is an LGA1150 based socket and that it doesn't cost more than the current combo I have which about £650. (To save money)