Refreshing spell duration

[Scrapheap]

If I cast a spell, say Luminous Armor, while it is already active will it renew the duration or do I just have a second instance of it ready to go when the first expires?

[Khatoblepas]

I believe that it creates a new instance of the spell on you, starting the duration when you cast the spell. You don't get any benefit from it, but once the first instance runs out, the second instance will still be up. You don't get to recoup the overlapping duration.

It does give you an additional buffer against dispelling your Luminous Armor, though, since you have two instances of it running instead of one.

[KillianHawkeye]

Additionally, you can't use this method to circumvent the sacrifice component of sanctified spells which takes effect when the spell's duration expires.

[Khedrac]

There's also the bonus that if a dispel magic is cast on you you have two spells up not one - so there's more chance you will still have one of them once the dispel is resolved.