I was cruising through high level spells and noticed the Create Demi-plane serie. All of them are nice but pretty intensive on the maintenance part, Day/lvl is nice but still... you don't always have a day or two to waste on recasting the spell(s) while adventuring.
The permanency alternative is horrendously expansive and we all know that it can be dispelled easily by any spellcaster you antagonized enough (The list is likely to be pretty damn long by the time you get to this level of power). Losing thousands of GP on a single spell is pretty painfull.
Then I remembered reading about Planar Traits...
Timeless for example (Emphasize mine):
Timeless: On planes with this trait, time still passes, but the effects of time are diminished. How the timeless trait affects certain activities or conditions such as hunger, thirst, aging, the effects of poison, and healing varies from plane to plane. The danger of a timeless plane is that once an individual leaves such a plane for one where time flows normally, conditions such as hunger and aging occur retroactively. If a plane is timeless with respect to magic, any spell cast with a noninstantaneous duration is permanent until dispelled.
It made *Tilt* in my head.
What if I shift to the Astral plane which happen to be Timeless then cast create Demiplan ? Do I have a cheap permanency-ed Demi-plan?