How Does Making a Skill Legendary Affect Spells?
All of the perks for that tree are reset, so you will lose stagger effects and other bonuses that leveling up gave you.
You do not lose the spells themselves, nor have to get back to a certain level to use them again. There isn't a skill level requirement for using spells, so long as you have enough magicka to use them. Option 3 is probably the most accurate, in that they'll be a lot less effective due to your skill level and associated perks resetting.
Be wary of making a skill you use frequently legendary, especially a combat one. Going with alteration or smithing would be a good idea in my opinion.
Making any Skill Legendary does two things:
- Resets the levels of the skill itself to level 15, and
- Returns the Perk points to you.
You will not lose knowledge of any spells, however, they will cost more to cast again. You will not lose the knowledge of Fireball, or the Master spells you’ve learned, and you won’t have to do master quests after the first time.
Spells seem to crawl down in cost to about 60% of their original through leveling a skill to 100 alone. Perks further reduce these amounts as you know. Without either, the spells you’re use to casting will cost a little over 3x as much in magicka.
Casting them may not be wise unless you are sure you have enough resources to finish the mission (think beyond each fight).
For instance, sneak into enemy camp (Or Shout self ethereal), cast Mass Paralysis, followed by Firestorm. This could work, and would give a lot to xp, with minimal casting, however, unless you have gear that makes all this free, I wouldn’t recommend it.
It seems to be better to use the minimal spell needed to get by- as experience is relative to the spell’s cost vs damage rate. Other schools, cast your highest level spells, as the situation calls for, and as long as you have enough magicka to survive the fight.
This is however NOT the case with new spells added through the creation club. Those do more damage, ramp up exponentially with perks, and return much, much lower experience. They are like an, “Oh, no. This was a mistake, I need a way out or it’s over” spell. Terrible for leveling destruction.
One of the main benefits for making a skill legendary (especially if it’s a class/racial skill), is you get to keep the health, stamina, magicka already collected. This is why you don’t have to give up casting any spells, as long as you’ve made the correct choices along the way. It’s ok to use a lower spell. No less a wizard.