DM Post: Sage Advice about Permanency vs Dispel

This sage advice is from Dragon 317 page 104 (under the D&D 3.5 ruleset) but for some reason was not put into the Official D&D 3.5 FAQ. It is, however, official content.

What happens when a personal, permanent spell effect is dispelled? For example, a wizard uses the permanency spell and pays 1,000 xp to make a darkvision spell permanent on herself. If an enemy spellcaster successfully dispels the darkvision spell, does the darkvision effect return after 1d4 rounds, as it would if the wizard were using a magic item?

No, when a permanent spell is dispelled, the effect is gone. If the wizard in your example wants another permanent darkvision effect, she has to cast darkvision and permanency again and spend another 1,000 xp.