Will the iPhone 4S become slow like the iPod touch fourth gen?

My iPod touch 4th gen was super fast now slow like all the other iPods. Will the iPhone 4S become slow because of the use? Is it the ram that makes the iPhone slow?

It's something to do with storage that slows it down, like empty all the open apps often (double tap the home button) and it should last longer before coming really slow but if you take up all the storage then yes it will be slow

You probably have a ton of apps open, double tap the home button to view open apps, hold finger down until the X shows, then close them out on that bottom row. It will be alot faster after doing that.