Your theory makes a lot of sense. Mine is a bit different, but I'm still trying to figure out if it works with Richard's youth returned in 'Wizard.'

I definitely agree that the spell to keep oneself youthful is something one casts every day and which then sticks - I think for me the problem is, what if Shota is 300? Why aren't there more wizards from centuries ago still hanging around causing trouble?

Or are there? ;)