Need Details about Leveling Up

[Bryan]

I created a customized Spellsword that only has light armor and short blade skill, all the rest are magic skills.

I already created "Span Int" and "Spam Wis" spells. I want to max out Int, Wis, and Endurance as quickly as possible, replacing the first one to max out with Speed.

How many points do I need to raise each skill to guarantee the +5 attribute bonus on level up? Also, how does the game decide when you level up? I am not and WILL NOT use any leveling mods!

[psychotron666]

You level up every time your major or minor skills increase 10 times.

The only way to get +5 is to get 10 increases in skills governed by that attribute during a level up.
Also what skills go up during your level up don't carry over to the next level up. So basically you do not want to increase your major or minor skills more than 10 times total between level up, and you instead want to increase your misc skills to get the bonuses.

Honestly I wouldn't bother with getting +5s, just play the game normally and stick with the +3 and +2 and don't turn it into a chore. But that's just my opinion. If you want to do that, go for it

[Hidden Legend]

Endurance governs three skills. Heavy Armour, Medium Armour and Spear so a combination of 10 upgrades across these skills between the levels will allow you a +5 bonus to increase Endurance. I hope that helps.

[Lobo de hielo]

As @psychotron666 said there is no real need to go 5/5/5.

But if you really want to and not have it as a chore, then the easiest and least wasteful way to do it is first a very careful character build.
You need a good powerful starter character but really only need 4 Majors at start at most.
Any other skills you know that will be useful later game you leave in the misc pile.
Knowing you want to raise Int/Endurance/Will you leave at least 1 of each skill in the misc pile. i.e Alchemy, spear, restoration.

Now just play the game and ignore for a few levels. There are mods which show what you have levelled up in. Once you have 8 levels out of the 10 reached go and buy the ones you need to get 5/5/5. Example you see you have raised 4 endurance and 4 willpower, you go and do lots of alchemy to raise int 10, it will not affect the 8/10 level up it shows but you will get the +5 int when levelling up. Now buy 6 spear that gets your endurance +5. Buy some restoration and finally buy 2 willpower form a skill in the Majors.

It might sound complicated, but is very easy and means you can play the game as you want most of the time. Just check your level ups after a time so you know when to go and buy them.

[Teralitha]

Google and youtube are your friends.

[Guts]

You can eventually max out all your stats even if you don't play completely optimally. Honestly, optimising your character can take the fun out of the game. I understand wanting to get endurance to 100 asap for the extra HP, but technically there is no max level in this game so you don't need to worry about that. If your skills are all at 100 but your attributes aren't, you can just go to jail for assault or something like that and your skills will degrade, which lets you keep levelling.

But if you REALLY want to power level: To get +5, it takes 10 skill levels of any kind that are governed by that attribute. To level up, it takes 10 skill levels in major or minor skills. Unless you plan to get the +5 from misc skill levels, it's a bad idea to keep levelling skills if you have a level waiting for you. No attribute benefits carry over to the next level if you overtrain your major and minor skills, and you'll have more levels waiting for you that you would need to train skills to get attributes for.

UESP wiki has examined the hell out of morrowind and I think it may be able to explain things better.
https://en.uesp.net/wiki/Morrowind:Level