I despise re-potting..... maybe this is partly or subconsciously why Vandaceous are my favorite. Keep a log of all your actions, fert./ water/ potting, EVERYTHING. Consistency is ultra critical. When I repot its only because I have to in order to keep them at their best. Typically its the addition of better fresher air and circulation that can lead to a boost in growth. (Unless, Ray, your using a particular type of acid

Also, Paphs and Phrags do the same for me (as per Ray's comments) but these, I'm sure, are already healthy plants that were potted correctly to begin with. Have you changed watering habits? Just as this addiction is habit forming, as such what are your care habits?