While Vimshottari Dasha (based on Moon’s nakshatra) works well for general life trends and health, Chara Dasha excels at predicting external circumstances , social status, and geographic movement. Many practitioners use both: Vimshottari for psychological timing, Chara for event-oriented predictions.
Use a reliable software (Jagannatha Hora is free and excellent) to get your Lagna and Rashi. Note: For Chara Dasha, the Lagna is often more important than the Moon.
The duration of a Chara Dasha period is determined by the relationship between a sign and its ruling planet. Standard Calculation Rules
by K.N. Rao: Widely considered the gold standard, this book details his extensive research and case studies. Unlocking the Power of Parasara's Chara Dasa