chao8971: I think one of the ones I made that sticks out in my mind is from the first time I played Fallout about 2 years ago. I remember I had costumed my character out and made him all I wanted him to be. I made him pretty darn powerful and decided for more power I should join the Brotherhood of Steel. I had been saving often in that game and once I got to the highly atomic the Glow area I did a save inside, my problem was I did not have a backup save besides that. I found that I could not leave the area without dying from radiation so I had to start all over again. That day thought me some valuable lessons, most importantly to keep at least two saves in a game like that.
If you've read the manual, they do warn you about this.
About saving.
We here at Vault-Tec highly suggest that you use more than one
save game slot at a time. We suggest that you start with slot 1, and
work your way down the list of slots. When you want to save a game
after slot 10, start over again at slot 1.
In appendix 1: hints and tips
Save Often
You have ten save game slots. Use them well. Before you get to
a new location, save your game. Before entering a dangerous looking
building, save your game. Before talking to an important looking
NPC, save your game. And use all of your save game slots. Don’t
keep saving over slot 1. If something goes drastically wrong, it’s better
to be able to move a couple of saved games back and restore from
there instead of having to start over from the very beginning.