In general there are three grades of hardness for wire.

Dead Soft
Half Hard
Full Hard

When metal has been heated and cooled quickly it is very soft and easy to bend. However, after you have worked it for awhile it gradually gets harder and harder to bend.

"Dead Soft" is the easiest to bend and move. However, without more work, it does not keep its shape very well.

Many, if most, projects call for half-hard wire. It is not as soft as dead soft, so is harder to bend, but keeps its shape better.

Full hard is sometimes called spring hard. It is hard to bend and tends to snap right back to its original shape.

Now here comes the fun part. All of these hardnesses can be changed back and forth.

i.e. Dead soft gets harder and harder as you work it. When you hammer a wire, the wire gets harder and the shape stays in better. You can also tumble it when you are done. Tumbling polishs the piece and also makes it harder. I use mainly dead soft wire because I know that I can harden it up when I am ready.

Sometimes when you are working a piece or forging it, it gets too hard. Then you have to anneal the piece. You do this by heating it and then plunging it into water to cool quickly. This is called annealing.

It has been my experience that a lot of beginners do not anneal enough. I have been thinking of writing a tutorial to explain the whys and hows of annealing.

Glo

I have an article on wire that you might find helpful, Fundamentals of Sterling Silver Wire.