I disagree. This maneuver should be done by every pilot with his airplane. Yes you learn first with an instructor , but I can think of all kinds of reasons why a pilot especially an experimental pilot would do stalls in his own plane. Every change you make to wings to make your plane slower, should be tested to see what actual changes you will experience. My opinion every pilot should practice stalls occasionally to keep current in those procedures. Stall practice at a safe altitude is not a dangerous maneuver
I also disagree. I practice stalls whenever I fly. I do normal power recovery stalls and what I was taught as whoppee stalls. I was taught this technique by a WW11 pilot. From a decent AGL you do not add power after the stall. You continue to hold back pressure on the elevator control and let the nose drop until the plane gains enough speed that it will fly back up to the stalling condition and stall again. I will do this 3 or 4 times before initiating a power on recovery. I don't understand why so many pilots fear stalls.