Relive, retry, repose. The three reasons for saving.
Once games became larger than a normal human’s reasonable play time frame (and I said normal. People who can finish Resident Evil in Insane mode three times in a row just with the pistol need not apply), the save feature became a must — mostly because it wasn’t feasible to wrap the game up in a single seating.
That is repose. That’s when you save the game because it’s time to go. Because you’re tired. Because you’re bored, even, but just in case you want to try some more… This is the rationale behind games like Legend of Zelda or Nethack – games where saving is merely a method to ensure you can continue some other time.
In Legend of Zelda, the gamestate is comprised of several different things, including number of heart containers, items acquired, amount left of different kinds of ammo, number of rupees, treasures and secrets discovered, and dungeons completed. During the game, player position and current health are also kept track of — however, these are not stored in the save file. In fact, the effect of dying is usually the same as of loading a game — Link appears coming out from the original cave with 3 filled hearts, no matter how many total containers have been achieved. Every time the player goes back to the game he has to fill-up on energy (be it by means of a fairy or simply collecting hearts) and move to the next dungeon. The only difference, if I remember correctly, is that if Link died within a dungeon the player had the option of resuming the game from the dungeon entrance.
Rogue (and Nethack, as most of its successors) had a self-destructing single save. The player would create his character and start venturing in the dungeons in search of the Amulet of Whatever. Death was permanent — getting killed by a critter or trap meant you’d be scored up and get your place at the hall of fame, if you deserved it, and then it was time to start again. If at some point the player would like to stop playing for a while, a “Save” option was available. However, as soon as the game was finished saving, the game would quit, and loading the save file would cause it to be deleted. This meant the character’s life was, like our own, fragile — and players soon learnt to respect the game’s monsters and to be genuinely scared before venturing to the next dungeon level with few hit points.
Jeanne d’Arc uses the same savegame style when the player needs to stop playing while in the middle of combat — as did Fire Emblem, Advance Wars and a couple of their predecessors, if I’m not mistaken.
We’ll see why when we speak about retry.