Yes, we know that this is ridiculously possible with Broken Steel, if not nearly done by default. I'm putting this here because the guides I've seen don't show exactly how the breakdown occurs, on a skill-by-skill basis. Instead, they focus on the amount of skillpoints that are fee to use. While helpful, it doesn't tell you the minimum investment required into the skills.
This guide is not meant to have the fastest, most efficient route to 100 in all skills; rather, it shows the minimum amount of investment required, assuming that the player will actually go out to earn the remainder by picking up skillbooks, bobbleheads, and a minimum amount of perks, specifically Comprehension and Almost Perfect.
To recap what we know:
*Each Special stat grants 2 skillpoints to skills it influences per increase, to a max of 20.
**Exception to this is LUCK, which grants 1/2 skillpoint to all skills per increase.
*Each skillbook provides 1 skillpoint.
**Said skillbooks provide 2 skillpoints if the comprehension perk is taken.
*There are 13 skills, each can go to 100. Total amount of skillpoints required are 1300.
*Each character is required to have 3 tag skills. Each tag skills has 15 points to start off.
So, to start this off, we'll look at our skill list after taking the Almost Perfect perk and collecting the SPECIAL bobbleheads (in that order.)
Barter- 25 committed
Big Guns- 25 committed
Energy Weapons- 25 committed
Explosives- 25 committed
Lockpick- 25 committed
Medicine- 25 committed
Melee Weapons- 25 committed
Repair- 25 committed
Science- 25 committed
Small Guns- 25 committed
Sneak- 25 committed
Speech- 25 committed
Unarmed- 25 committed
Not bad, really. Without doing much wasteland scavving, our skills are already a quarter of the way there. Next, we'll apply the bobbleheads for Skills.
Barter- 35 committed
Big Guns- 35 committed
Energy Weapons- 35 committed
Explosives- 35 committed
Lockpick- 35 committed
Medicine- 35 committed
Melee Weapons- 35 committed
Repair- 35 committed
Science- 35 committed
Small Guns- 35 committed
Sneak- 35 committed
Speech- 35 committed
Unarmed- 35 committed
Not as good of an increase as the ones from the SPECIAL, but that's still 10%. Now, let's apply the skillbooks. For simplicity's sake, we're not counting the Tenpenny glitch for another book, or the respawning books.
Barter- 58 committed
Big Guns- 60 committed
Energy Weapons- 60 committed
Explosives- 60 committed
Lockpick- 60 committed
Medicine- 60 committed
Melee Weapons- 60 committed
Repair- 60 committed
Science- 60 committed
Small Guns- 60 committed
Sneak- 60 committed
Speech- 60 committed
Unarmed- 60 committed
Wow. A little over half of the way there now. Note that we can only find 23 books for Barter. Now, let's recalculate that, adding in the comprehension perk.
Barter- 81 committed
Big Guns- 85 committed
Energy Weapons- 85 committed
Explosives- 85 committed
Lockpick- 85 committed
Medicine- 85 committed
Melee Weapons- 85 committed
Repair- 85 committed
Science- 85 committed
Small Guns- 85 committed
Sneak- 85 committed
Speech- 85 committed
Unarmed- 85 committed
Well... damn. Almost there, and we have yet to put in *any* skill points. Three tag skills means that, at this point, three skills are likely at 100. Unless one of the tag skills is Barter, which pushes it to 96. Four points away.
That means the absolute minimum of investment is 15 skillpoints into the remaining skills (and 19 or 4 for Barter.) Now, for some math! We'll do the lump-sum technique of seeing how many skillpoints that must be committed over 30 levels. For simplicity's sake, we'll be assuming that Barter is not a tag skill.
So, 9x15=135
135+19 (the points for Barter)=154. This is the absolute minimum number of points we can freely play around with.
154รท30=5.1333333(etc.). So, that means at minimum, we need 5 points and some change per level up to get it all cleared out. So, 6 points per level is more than enough for our purposes.
Ok, let's see the minimum amount of Intelligence required to get those 6 points per level.
Intelligence increases skill point gain per level by one... and the base skill point gain by level is...
*squints*
... 10. The base skill points we get for leveling is 10. And since Intelligence can only go down to 1, that means each level up we get a minimum of 11 skillpoints per level.
No wonder it's absurdly easy to get to 100 in all skills with Broken Steel. It doesn't really matter how high your Intelligence stat is, or how many points you invest into each skill. So long as you put a minimum of 15 points into your non-tag skills (and 19 or 4 into Barter) by the time you hit 30, you shouldn't have any excuse not to hit 100 in all skills, provided you make it a point to find all the skill books, collect all the bobbleheads, and take comprehension and the Almost Perfect perk.