that's right, if you never reload, you'll have to do 3 playthroughs with completely different decisions in order to enjoy full game content.
You make is sound as though that's a bad thing. With so many ways to play this game, I'd rather side with a different faction for each play through, and make different decisions with each. For instance, I sided with Goodsprings for that first real quest. In that play through, I also chose the NCR. Next time, I will probably side with the Powder Gangers for that quest. Why would you want such a stuttered game as to play every option in a single play through? Doesn't it get terribly fractured?
As for saves, I'm on the Xbox and I have 100 (max). When I started hearing about 20 corrupted files, I figured I'd just make more saves, and hope. I have zero clue as to whether or not the additional saves could be helpful though. I'm not on hardcoe, so I don't have to worry about companions dying. I often save before a big decision, if I have no idea what it's going to do. For instance, I went into the irradiated vault without a quest, so when it came to decision time, I didn't know that one option would remove the other. I didn't know what the buttons would do really. So, I saved first. When I found that I could only have one option, and not both, I reloaded and chose the other. Maybe that's not role-playing, but I really didn't like the first option I went with because it was so far off from what my character would do. On the other hand, with the info I had available, I suppose it was.