While I was exploring the ideas of sustaining a Spell and the consequences of destroying a Spirit by Spell Binding in order to get a full 24 hours of use out of a sustained spell, I came across a Spirit of Man and one of there Optional Powers that a Summoner could choose... Innate Spell. When going to Force 3 or higher, you can opt for the Spirit you summon to have one of your spells as an innate power that works exactly the same as if you were casting it.

Now in the main Shadowrun book, you can order a summoned Spirit to use one of it's powers continuously for only 1 service use... Lets say your Mage has Improved Agility as a Spell, summons a Spirit of Man with the optional power Innate Spell: Improved Agility, can you order your Spirit to cast and sustain the spell upon an ally as just one use? Hell, even 2 uses for the casting and then sustaining... I just wanted some clarification on this since I've been focusing so much on Binding and Spell Binding rather then this ability that Spirits of Man have.

Yeah, they can sustain it for only 1 service. Note however, that afaik it'll last 12 hours at most, since spirits disappear at sundown/sunrise. If you use a bound spirit, the spirit will charge you 1 service per day/night cycle, or you can pay its force rating in Karma to have it sustain the spell for 1 year and 1 day.

Yeah I figured the 12 hour (less since I doubt your gonna be Summoning a Spirit right after sunrise/sunset to get the full 12 hour potential) would still apply... I was just looking to hit the mark of having a Sustained Spell for about an Hour with a Spirits help and going about it in the Binding way seemed a bit useless. Having a Spell Sustained for a few rounds at a time seemed a bit awkward for those missions you need to change up plans on the fly and you might need to help a team mate out.

In theory, Long Term Binding of the Spirit will net you the sustained spell for a year and a day... it only costs Karma equal to your Spirit's Force, and reduces any Services to that single Task dictated in Long Term Binding...

EDIT: Damn, Missed that last sentence from Elfenlied's post... He already covered that...

I mean that is an awesome thing to keep in mind, but I really just needed the usefulness of not having -2 or higher while sustaining a Spell for a few hours.... Besides, sustaining a Spell for that long is bound to draw some unwanted attention from the Astral Plane.

No real difference from slapping a spell into a Spell Sustaining Foci every morning when you wake up though...

Not that this is the point of the discussion, but I believe the spirit has full use of the spell and casts it all by himself. For example, suppose you let him have a 'copy' of your powerbolt spell, then order him to "kill those guys over there with powerbolts until they're all paralysed by death" then that's one service spent and the spirit uses his own Magic and Spellcasting ratings to dish out the pain.