You can make a spell last all day.
Prerequisite(s): Extend Spell.
BENEFIT
Spells with a fixed or personal range that have a non-static duration can have their duration increased to 24 hours. Spells of instantaneous duration cannot be affected by this feat, nor can spells whose effects are discharged or effects that cause hit point damage or healing. You don’t need to maintain concentration on prolonged detect spells (such as detect magic) for you to be aware of the mere presence or absence of the subject detected, but gaining additional information requires concentration as normal.
Fixed range spells are spells that note a specific number of feet, like 30 ft, but not close, medium, or long-range. Fixed range spells also do not include touch range spells, ‘Main D&D FAQ pg24’.
Spells that have durations based on caster level like 1 round/level count for this metamagic feat, though spells that note a specific number like 1 minute are not affected.
MP Increase: +6 (a prolonged spell costs 6 additional MP more than the actual MP cost of the spell.)
Special: Spells affected by prolong cannot have any other metamagic feats used with them, nor do the spells benefit from any other effect that would increase duration.