Regular death, where a character dies but comes back, isn't really that rare IME. The most common reason being a "1" on a death save, with extra failures due to AoEs being somewhat common. Occasionally you'll die because a monster begins to eat you or a vengeful, intelligent enemies confirms the kill. The likelihood of this happening significantly lowers at level 3, and while it drops again at level 5, it never fully goes away.
Regular death before level 5 almost always results in permanent death, since the party lacks access to resurrection magic, but permanent death after level 5 is pretty rare. Normally it happens because it's the cleric/healer with the resurrection magic is the one killed, but after a certain point, you can just carry at least part of the corpse back to town. Occasionally the player will fall to something particularly nasty, requiring far more than simple resurrection magic, usually a Wish. The most memorable in 5E for me was in my first campaign, when a PCs hit with a Confusion spell wandered off the edge of the Demonweb, falling forever through the Abyss.
Regular death before level 5 almost always results in permanent death, since the party lacks access to resurrection magic, but permanent death after level 5 is pretty rare. Normally it happens because it's the cleric/healer with the resurrection magic is the one killed, but after a certain point, you can just carry at least part of the corpse back to town. Occasionally the player will fall to something particularly nasty, requiring far more than simple resurrection magic, usually a Wish. The most memorable in 5E for me was in my first campaign, when a PCs hit with a Confusion spell wandered off the edge of the Demonweb, falling forever through the Abyss.