Hot or Not

All the reviews I have read of audio equipment mention that you got to let the equipment warm up for say half an hour before it sounds right. So if I am in say England, 1 to 5 degrees Centigrade in Winter to 14 - 28 degrees Centigrade in summer. So assuming that the Class A amp goes up say....15 Centrigrade. That means the amp sounds great at anything from 20 to 48 Centigrade. And if you are in India and the ambient is 32 Centigrade and after warm up we are pushing 50 Centigrade, then thats when the amp sounds wonderful?
Then we come to another part of the problem with all this warm up business. We also know that electronics produce less noise i.e. added free distortion at low tempratures. However if para one above holds true, then this applies in reverse to audio equipment.
Confusion. I have never heard better sound in warm amp. I always thought that heat was the enemy of electronics and would reduce the life of components.