The Role of Saving in Games

Save games have evolved in video games pretty much like everything else has.

1: In the beginning...
The first "quest" games--the ones that have you go an epic journey, which require various sitdowns to complete the game--sometimes had no save games at all. You either had to beat the game in one sitting or start over. Or other times the game would save, but you would only get a fixed amount of lives to reach the ending, which was a very hard thing to accomplish. Either way, these games were ridiculously hard and frustrating.
Think: Mario, Sonic

2: Passwords
And then somewhere along the line the idea was to include a password with each level. Then, when you quit your game, your progress was lost, but your game could be resumed from that level with a password. The problem was, you either forgot the password, or some levels would be so long, that hours passed until the next password. Not very intuitive, but better than nothing.
Think: Out of this World, Flashback

3: Save points
So, you still couldn't save wherever you wanted, but you could save at specific "save points" that the designers included in some levels. Lots of RPGs used this, and you could also save on the world map. This method was fairly straightforward and functional for the player, and worked well, except when save points were spaced out over an hour of gameplay, making it extremely hard to decide if you should save your health potions, thinking that there might be a save point around the corner, or use your health potions because you were still hours away.
Think: Final Fantasy, Chrono Trigger

4: Unlockable Content and Autosaving
In this type of savegame whatever thingamajig, you couldn't save anywhere in the game really. The game automatically decided that after you completed a level, that level was unlocked. Then you could resume your progress from each level. Some of these games also came with autosaves during the level, so you wouldn't have to restart from the beginning of the level. This method works fairly well, and the only setback is when autosaves are spaced too far apart.
Think: Goldeneye (N64), Halo

5: The Universal Save
And today, 90% of games use the UNIVERSAL SAVE method (at least PC games anyway). You can save at anytime, and anywhere you want just by pressing a key. You can play for five minutes and leave, or you can play for three hours, then save and leave.
Think: Command & Conquer, Half-Life, Monkey Island, Roller Coaster Tycoon, Call of Duty

The main bulk of PC games use the universal save, and a good chunk of console games use the unlockable content and autosave. I don't know if console games have less memory, or maybe they just want to make it more challenging.

You'd think a Universal Save would always be the best option, but the one main argument I've heard for the Save point system is: "[the save point system] increases tension because you aren't always safe, and you have to tough it out until you can reach the next [save point]."
It's an extremely valid argument, and it makes me wonder if the Universal Save isn't always the best option. With the universal save, sometimes you feel too cosy with the save button always at your fingertips, but I've grown accustomed to playing a game in the moment, and not worrying about my consequences too much.

Anyway, that's all.