Questions
Can I learn this on my own through DVDs or books?
Yes, and you might progress in the posture and breath work, through self-practice.
The benefits of a teacher are many, including an alternate perspective. By observing you, a teacher can add a lot to your experience, shift you in subtle ways you may never have discovered on your own, and help you move forward. At the very least, with a few tips and encouragement from an experienced teacher, it's easier to avoid some of the frustrations that you may experience as a beginner. A trained eye can also help you prevent injuries.
In the role of mentor your instructor sets the tone of your yoga practice. For my classes the givens of safety, non-competition and attentiveness also allows the group to be about community, sharing, unrestrictedness and joy.
You might eventually get bored of a DVD. A good teacher will have his/her own personal practice and will be on a journey alongside yours. With a good teacher, every lesson is different.
I'm not flexible. What if I can't get into a pose?
As with anything, it's important to start out slowly. Progress happens with baby steps. One day you may find yourself in a pose a certain way, but next time your experience will be something different. More importantly, what happens is that you become more aware of yourself and you notice the differences in each practice.
Yoga isn't about flexibility. It's not about stretching and strength. Over time we become familiar with the poses and learn to play in and around them. Your development is about removing the restrictions to your own mobility and energy levels, and on what you only think you can and can't do.
What if I don't have enough time?
Busy-ness is an affliction of modern living: too many things to do, places to go, and people to see in our daily lives. Practicing yoga may help open one's mind and re-prioritize your relationship with time: either by having more energy for your tasks, or having a new approach to those tasks.
Committing to yoga practice prioritizes planning downtime: to restore, to de-stress. When you're under stress, your body goes into the "fight-or-flight" response, and too much stress leads to a variety of potential health risks. As an example: an overabundance of the stress hormone cortisol is associated with weight gain, particularly unhealthy fat storage around the midsection. By controlling stress, we can moderate weight gain.
You can practice yoga fifteen minutes every day, or more intensely several times a week. Whatever the case, you will almost always feel better afterwards.