Franniee has the right idea
Franniee has the essence of the answer. Permit me to elaborate.
First, Kilted Kat, you have to know, really know, what a progressed chart is. I'm not sure what your exposure or experience with astrology consists of, so I'll make a short-story long. "Progressions" are generally seen as any chart which is based on "symbolic time". There are many types of progression charts. The two most popular are called Secondary Progressions and Solar Arc Progressions. Both are based on a "one-day equals one-year" concept. For example, if you wished to look at your thirty-fifth year, you would look at a chart cast for the 35th day after your day of birth.
During any single day the Sun advances a little less than one degree, the Moon advances 12 to 15 degrees, the personal planets advance a varying rates up to a couple of degrees, the outer planets take longer -- Pluto averaging some 20 years in a sign. Therefore, it is highly unlikely that the outer planets will move out of one sign and into another sign for most people.
Also, planets may be retrograde at birth and end up wandering around within a degree or two of their birth location for 30 or 60 or more days -- this equating to 30 or 60 or more years of time.
That being said, let's return to the different types of progressed charts. The Secondary Progression chart advances each astrological body by its daily motion at/after birth. Some software programs permit you to apply the birth date's motion to each/every day after birth, or to use the actual motions for the number of days after birth to find the total motion for a given day/year. (I'll let you think about the difference in the two examples given). The MC angle can also be progressed by various rates -- the mean rate, the current rate, the actual rate for the number of days/years after birth. Astrologers have often argued heatedly over which of the different approaches to take.
The Solar Arc Progression charts advance all astrological bodies by the Sun's rate of motion. Again, you can apply different rates; the rate of motion on the day of birth, the average or "mean" rate, the actual rate over time.
Finally, you have to consider the purpose for choosing and using Secondary or Solar Arc progressions. These two charts are different from each other and are used (or should be used) for different purposes. Each of the list members should think about this and try to determine exactly what the differences mean.
Back in "pre-computer" days, astrologers and students did not casually "whip" off a chart -- it took to much time to calculate, so charts weren't calculated and drawn up unless you knew what you needed and how you were to going to use the chart. Today every clicks a few keys and then receives what they asked for -- the problem being that many don't understand what they ask for or what to do with it. So, at this point everyone should google all of these questions and find out the answers for themselves. Do think about why and when you might use these types of charts. Dave.