Just look at the PHB and DMG: you find only half a page speaking about alignmnent and in a very general ways.
If you go through older editions (such as 2nd) you find many more pages, examples, rules about changing it, and penalties for not behaving properly.
I went to distrust many of those pages in older editions and some of players' behaviours too: some players used to choose evil alingment only to have an excuse to act selfishly in order to gain more wealth and magic than their comrades.
Too many considered alignment as a rigid code of conduct while I started to view alignments as a tool to give depth to a character's personality.
Example: A neutral evil character might well be selfish and greedy, but he might still be known to be a fine and upstanding citizen, pious in his devotion to gods and courteous in all his dealings. Maybe his parents gave him a very costly education, but at the same time they instilled him with great ambition. Maybe he grew up a bit wild and with a wicked streak, but had a religious awakening after nearly dying from lung fever and being healed by a priest. So he’s neutral evil, not a paragon of virtue perhaps, but not an altogether bad man either.
Use alignment in a positive way, to add fun to role-playing and be not a prison for PCs' will.