Pick a planet
We each have a chart that contains the whole set of planets, signs and houses that everyone else has. What is different for each of us is how they are arranged. As several have noted, we continue to express the birth chart throughout our lives. That's fine -- but is it enough? Progressions and transits are two of the several tools we have to look at opportunities that come up from time to time WHEN WE CAN MAKE A CHANGE. If you have an aspect pattern of two or three planets in your chart, you know how you express it. Often this expression focuses more on one factor and less on another factor.
If you have options, you should express them all (my quote). We can do two things to more fully or differently express ourselves. First, we can make sure that we give each planet in our chart an opportunity to truly be part of us. Don't focus on Mars when the Moon needs just as much space. Second, each major transit or progression to a natal aspect pattern from a planet that is in that natal pattern gives us a chance to focus on that particular energy. When another transiting or progressing planet also hits that natal aspect pattern at the same time, THEN YOU HAVE AN OPPORTUNITY TO EXPAND YOUR HABITUAL EXPRESSION OF THAT NATAL ASPECT PATTERN.
Expanding your sensitivity and expression is called growth. You can literally grow out of your chart as you knew it at one point. Keep in mind that many are used to looking only at a few aspects such as the conjunction, opposition, trine, square, etc. There are other aspects that are just as important -- they are found when you divide the circle by 5 or by 7 for example.
One of the biggest areas that is overlooked is that of EQUAL ARCS. Pick two planets in your chart that you feel are significnat in your life's experience. Measure the arc in degrees and minutes between them. YOU NOW HAVE TWO OPTIONS.
First, when ever those two planets re-establish that arc, no matter where they are in your chart, their energy comes back into your life in a big way. You can channel this familiar engergy into any other planet that they contact (by hard aspect or by mid-point) and thereby add a new planet and form of expression into your life.
Second, find any other pair of planets in your chart that have a closely similar arc. If one/more exists, then that pair of planets and the first pair of planets can share a common mid-point. When ever that mid-point is transited by any of the several planets involved, then the whole group of planets (and the combined energies they represent) can be expressed.
The point of this is that you can change your chart by growing from its perceived limitations and by adding complexities and expanded opportunities to it. Dave.