Rasputin's Guide to Magic XI (Cont.): There are downsides to this ritual. Number one is now that your reflection is de-synced. While they can easily hide (making great spies), this may make people mistake you for a vampire, ghost, or other supernatural creature without a reflection. This can lead to false convictions, and attempts to 'purify' you. Additionally, if your reflection does follow you, and you have followed the recommendation to change their appearance, others might believe you are under some form of enchantment, and attempt to subtly "free" you. For low level spellcasters who got lucky (or high level ones who use many ongoing low-level enchantments), this can cause issues and inconvenience when such people (acting on kindness) accidentally disenchant something you were using, and you'll need to fix that. It is still recommended to change their appearance, as it can help remind you they're a person now and treat them kindly, as well as ensure your spells/enchantments and rituals to assist them don't accidentally target you by mistake.
Note: They will be much weaker than you. A complete novice, and it can take them years to train up to your skill level. Magic inside mirrors is reversed after all, and they need to learn a spell backwards to make it work. As such, please treat them like a new apprentice, rather than a new college.
Note 2: Especially strong wizards can overcome the limitations with the ritual seen on page 247 of volume XVII to grow a new reflection that matches you perfectly.