Youth is a weird prerequisite for Steal Youth

[GurpsObserver]

The Steal Youth spell has the spell Youth as pre-requisite, but it seems that makes it superfluous.

The Youth spell costs 100 energy to remove one year from the subject's age, with one try per month, and can be used on anyone including the caster.

Steal Youth costs 10-30 energy to take 2-6 years of life from a subject and transfer 1-3 to the caster, but a critical failure costs 20 years of aging and a point of IQ. It is also resisted, so the effective energy costs and risk of critical failure are increased for repeat castings.

Youth is the better spell to cast for personal immortality, since it avoids the risk of cumulative IQ loss, avoids making enemies by destroying the lives of sacrifices, and falls within the 100 energy ceremonial casting limit for nonmage spectators without Powerstones. And one could get ceremonial support with the promise of Youth (or by building goodwill with the huge profits of Youth castings).

Burning 2 years of someone's life to save perhaps 80 energy (when that person could generate over a thousand energy via Steal ST) seems like a crazy tradeoff. To be fair, Steal Youth could be helpful for a nasty necromancer who cannot get access to large amounts of energy or ceremonial supporters, and so engages in 'slash-and-burn' life-extension, but I would suggest a better approach would be to change the pre-requisites so that a pure necromancer can master Steal Youth without Youth, e.g. Age and Magery 3 (since Age can be learned purely from necromancy).

Those pre-requisites allow for eternally youthful necromancers living off the life of others, who aren't automatically able to renew the youth of others or skip the sacrifices for trivial additional work.