How to add new music into iPhone 4S running on iOS6?

I try to add music and it says that the "iPhone will erase and sync"

How to add new music without deleting my old collection?

"I try to add music"

How? Yes, that matters.

"How to add new music without deleting my old collection?"

Have you tried setting your iPhone or manual management of music and video? That's what I do on my iPod and in nearly 3 years, I've never lost music putting new music on.

In any event, why isn't your music backed up to something like CDR, DVDR or flash? Computers crash, iPods get stolen or lost, or they all get replaced. How are you planning on keeping your music then? It's just odd to me that for years I've seen questions like this one posted by people who spend hundreds of dollars on high technology media gadgets yet can't be bothered to take simple and cheap steps to protect their media.