If you are planning to do some off-piste skiing or boarding, it is imperative that you go with a guide who knows the area. Without guidance, you run a much greater risk of serious injury or worse from avalanches and other unforeseen hazards (crevasses and cliffs, for instance).
In many instances, the local ski schools will have a number of qualified instructors who will act as guides. However, depending on where you want to go, you might sometimes need to hire a licensed mountain guide (guide de haute montagne in France). You will need to make enquiries locally when you get to the resort.
Your guide should be trained in avalanche safety techniques and will be able to assess the stability of the snow, weigh up the risks and choose the safest routes possible. Always follow your guide's instructions - for instance, if your guide tells you not to ski ahead of him (or her), don't.
Some people adopt the rule that you should never ski off-piste without a qualified guide. But many highly experienced skiers take the view that this is unrealistic, and that what is essential is awareness of the risks and familiarity with the terrain. In the end, it is up to the individual to judge what assistance he or she needs.
By the same token, each individual needs to evaluate the advice they are given by a guide, qualified or not. Guides are fallible, and not always as good at gauging the competence of those they are guiding as at negotiating mountains. Ultimately, you are responsible for yourself.
Take a look at our resources page for some in resort ski guiding services.
For more ski safety, tips and mountain advice: All ski tips | Ski lifts | Pistes | Accidents and First Aid | Altitude sickness | Starting snowboarding | Sunburn and snowblindness | Learning to ski tips | ISF rules | Weather | Off-piste safety | On-piste safety