What transits are

Your natal chart is fixed at birth. Transits are where the planets are right now in the sky. When a transiting planet hits a natal placement, it activates that placement for the duration of the contact.

The big timing gates

• Saturn return (~age 28-30, 57-60, 86-89): the most famous transit. Saturn comes back to the place it was at your birth and forces a structural review of your life. Heaviest at the first return.
• Jupiter return (every ~12 years): opportunity expansion, faith renewal. Comes at age 12, 24, 36, 48, 60, 72.
• Uranus opposition (~age 41-44): the "midlife crisis" transit. Uranus is halfway around your chart, opposite its natal position, demanding authenticity.
• Chiron return (~age 50-51): the wounded-healer placement comes back. A return to early life themes with adult resources.

Vedic Mahadasha vs Western transits

These two systems both track timing but differently. Western transits ask "what's the sky doing relative to your chart right now?" Vedic Mahadasha asks "what 6 to 20 year period of your life are you in?" House Call uses both: they often confirm each other but sometimes diverge, and the divergence is informative.

Eclipses

Solar and lunar eclipses are amplifier moments. An eclipse that hits a natal placement (within ~3°) tends to mark a turning point in that life-area within 6 months either side of the eclipse date.

A House Call reading puts all three traditions on one chart and shows where they agree and where they do not. For why a Western and a Vedic chart can name different signs for the same Sun, see why the charts disagree.

Read next: Saturn return in three traditions, with your dates.