Changing Strings

excerpted from www.beststudentviolins.com:
How do you change a violin or string, or restring a violin?

If you're going to replace all the strings, I would not take them all off at once, but replace them one at a time, the outside strings first, then the inside. By doing them one at a time you can retain the placement of the bridge and also better avoid having the soundpost fall. It's also crucial that you put the strings in exactly the correct/same peg, and not change that. If the pegs are lower left, upper left, upper right, lower right, the strings need to be: G, D, A and E.

1. Carefully examine the strings and the way they are attached to your tailpiece and to the pegs in the peg box.
2. Remove the string.
3. Attach the new string to the tailpiece, either to the fine tuner or looping through the hole in the tailpiece, depending on the way it was before, if you're not changing the setup; the top string (E on violin) will normally always have a fine tuner; the other strings may or may not use a fine tuner. If you have a Wittner style tailpiece, all four fine tuners will be built in.
4. If you're changing the E, make sure the "doughnut"--the little either sleeve or black, doughnut shaped rubber ring--is going to be in place under the string when it crosses the bridge.
5. Pull the string towards the pegbox, and insert the tip of the string into the hole of the appropriate peg.
6. Turn the string in the direction away from you, if the violin or viola is facing you. As you turn the peg away from you, be sure that you wind the string against the side of the peg box. Again, make double sure that the strings are attached to the correct peg; otherwise they may cross each other and cause a problem, and the balance will be off.
7. Tighten it a bit but not too tight, get the pitch from a tuner or another violin, and tighten the string slightly higher than the prescribed pitch (so it can stretch).
8. Repeat this process on other strings you wish to change.
9. While doing this, you might also want to examine the nut to see that it's not too deep, or so rough that it may break the string, especially on the top string. If it needs smoothing, you may need to take it to a luthier to do that.
10. When you're through changing the strings I would tune the one(s) changed up slightly, and leave the instrument out (or with the case open, if you can), so the new string(s) can adjust more quickly. Before you play, you will of course tune carefully.

also:

• after changing strings, check the bridge to make sure it's still standing up straight (perpendicular to the surface of the violin)
• I advise changing all four strings at once instead of one at a time.
• strings should be changed 2-4 times per year. I usually change my strings once per season.
• for most students, Dominant strings are the best combination of value and quality.