A progression is the natal chart moved forward by one day per year. So, if you are turning 30 years old, your progressed chart is identical to a snapshot of the sky 30 days after your birth. Progressions reveal how natal potential is currently being expressed. They are also useful when predicting timing, based on transits to the progressed planets.
Typically only the faster-moving inner planets (Sun, Moon, Mercury, Venus, and Mars) and the angles make significant changes during your lifetime. However, it’s important to note if an outer planet or Lunar Node changes sign, house, or direction, because this marks a significant life event. The progressed planets have the same energetic meanings as natal planets, however, the sign/house changes reflect your growing consciousness of this energy.
The fastest mover in the progressed chart is the Moon: it changes every 2.5 years or so. The PR Moon describes your evolving needs. Because your inner emotional state is reflected in the nature of your relationships, the progressed Moon often indicates how these change as well. For example, when your PR Moon moves from Virgo to Libra, you go from focusing on work, health, and routines, to preferring harmonious relationships. Your needs have moved from practical to social, and you are more likely to compromise and focus on graciousness/attractiveness.
The progressed Moon also moves through natal houses (not to be confused with the Progressed houses), and your general emotional state is self-expressive/optimistic when in houses 1, 5, and 9, materialistic/practical in houses 2, 6, and 10, intellectual/social in houses 3, 7, and 11, and emotional/intuitive in houses 4, 8, and 12.
Progression changes can be quite dramatic. You can feel instantly different about things you were hell-bent on when your Moon changes from a fixed sign to a mutable one, for example. Likewise, when a PR planet makes an aspect to a natal one, this can indicate timing of events, such as the beginning of a relationship, the end of a career, etc. For this reason, the progressed chart is a great predictive tool.
The progressed chart has its own angles and houses; this is because the Ascendant progresses, therefore slowly shifting all angles/house cusps. So your PR Moon may be moving through your natal 8th house, but in your progressed 6th house. This adds another layer to the complexity of your evolving needs. For example, the person above may be focused on intimacy within relationships (8H), specifically with co-workers (PR 6H). Or they may be learning more about the psychology behind people’s motivations (H8) as a requirement for their daily job (PR 6H).