My Dtps. Malibu Merlot began blooming in Jan 2012, and it is still in full bloom. It has not dropped any flowers, and they aren't even tatty looking. I recently repotted the plant a couple of weeks ago, and I thought that would initiate spike death......not even one wilted flower yet!
It must have a great deal to do with the climate (temperature). Phalaenopsis flowers are long lasting but those must be some kind of record. All of my hybrids just plain quit at the end of May because of the heat and low humidity that we have in the spring, however; those with equestris in the background "keep on truckin".