Future Android Update Question

[iTech278]

Hello!

I have been looking at Android recently, and I read that Google's Nexus phones will be the first to receive future Android updates, and then other phones after that. My question is: how long would it take Samsung phones, such as the Galaxy S4, to receive the updates? I know there probably isn't a definite answer, but what would be a reasonable time frame as to how long it would take from the release of the update?

Thanks!