The bridge is a vital part of the violin but like the rest of the instrument, it needs special care for it to do its job 100%. As with the soundpost, the bridge is not glued in place but held down by pressure; in the case of the violin it is roughly 40 pounds of downward force! If you’ve ever heard a bridge fall over, you know just how much power there is.
The bridge is constantly in motion in one direction or another so it’s important for the player to keep careful watch over it and put it back where it belongs. The most common motion is for the top of the bridge to lean towards the fingerboard. This happens because as you tune the instrument, the strings are being pulled towards the pegs and the bridge will go right along with them. Luthiers put in graphite on the bridge notes to help minimize this, but it cannot be fully prevented. At least once a week, it is a good idea to look at the bridge from the side and ensure its standing up straight, at 90 degrees on the tailpiece side. If you need to lean it back, or forward, anchor you pinky and thumb on the fingerboard and use your 3 middle fingers to gently nudge it in the direction you want to go. Move slowly and check often, you don’t want to overdo it.
If the bridge is allowed to go off 90 degrees for long, that 40 pounds of force will warp the bridge, and if that happens the bridge must be replaced. With proper care, it’s possible to get well over a decade of service out of your bridge.
Part of a yearly maintenance schedule at a reputable violin shop will be to reapply the graphite to your bridge, helping keep it in place. Also, a trained Luthier will make sure the feet of the bridge are where they need to be for the best sound production.