The best reason to know the future through astrology is to prepare. Forewarned really is forearmed. Just because you know there's the likelihood of rain ahead doesn't mean YOU have to get wet! Instead, you can factor in the information, and pack raingear. That becomes your choice once you're informed. Because you took the time to learn the forecast you're empowered to do something about it. Too often people hear that they're entering a so-called "bad" dasha and then they freak out. They fill their minds with horrible imaginings instead of taking the next step: get more information about what the dasha means, and use the information to their advantage to empower their lives.
I do believe that certain events are fated in our life. However, I don't believe it's helpful to think in terms of fate, because it paralyzes our will to take positive action and improve our karma. For this reason, it's better to think of the chart as revealing trends and likelihoods, not inevitibilities. The planetary positions reveal the trends and patterns that we ourselves have set in motion in the past. It's like you're driving down the highway and the sign says, "New York City 10 miles." If you're driving 60 miles per hour than we can predict you'll be there in 10 minutes. You chose to go to New York and you can take the next exit and change course at any time.
The best way to prepare for the future is to stay present in the moment. Use the knowledge of the future to set yourself on the right path, and then simply live your life well.