How important is stretching before a work out?

It's a good idea to stretch each body part that you will be working out for 8-12 seconds before working out that part of your body.  After you work out that part, you should stretch for 15-20 seconds.  I hope this helps.  In short, it's a good idea to stretch a bit before you work out, but after, make sure to take some time. 

It's important to begin your workout gradually, allowing your body and muscles to warm up before increasing intensity and strain. It could prevent injuries further, and it usually improves the workout significantly. Don't forget to cool down and stretch after the workout as well.

Stretching before a workout is very important, especially if you're working with free weights. No need to over do the stretching, but spend at least 5-10min at the beginning - run the treadmill, walk the stepper - something that moves your muscles.

Don't forget to do the same at the end of the workout. 

Stretching is a preventive measure and it is very important because it helps to prevent injuries.  Many injuries are hard to eliminate such as running injuries which occur in the feet, ankles, knees and legs, but much can be done to keep them to a minimum.  Prevention measures include stretching exercises, and equally important are proper warm-ups and cool-downs.

it is really important so you won't get hurt