Switchable

B34 discusses switchability under 'Turning Advantages On and Off.
B63 lists it as a +10% enhancement for Invisibility, while it is a +100% enhancement for Mana Damper (B67) Mana Enhancer (B68) Psi-Static (B78)
==alternatives==
Mixed messages exist on whether non-switchable (always on) abilities can be made switchable by other modifiers without the enhancement...
*H17 "change Invisibility to Invisibility (Costs Fatigue, 2 FP, -10%; Substantial Only, -10%; Switchable, +10%)."
*PP17 "Costs Fatigue and Requires Concentrate are an inexpensive alternative to Switchable"
==free for some DR==
CEF 10
:If there is no drawback, being switchable is a 0% special effect.
:This applies, for example, to Damage Resistance, which can be either always on or switchable for the same point cost.
:(However, Damage Resistance with Can’t Wear Armor is inconvenient, so making it Switchable is an enhancement.)
:See Switchable (pp. 17-18) for more
This isn't entirely true though: having DR is inconvenient if you want to avoid hurting people (though that's not a risk with flexible DR) or if you want to be able to suffer harm (to blend in) or get afflicted.
==not needing switchable vs Switchable==
Kromm at http://forums.sjgames.com/showpost.php?p=340291&postcount=8
*Only add Switchable if no other factor intrinsic to the ability (time, running out of FP, etc.) switches the advantage on or off.
*Switchable isn't required if the ability only turns on in the first place if you pay FP or trigger a limited use.
One key aspect of Switchability isn't just "I can switch it off" but also "I can switch it off when I want it off".
P153 under Always On mentions that Costs Fatigue gives discrete "uses", while under Transient mentions "uses" of finite duration (1 minute is finite).
The middle section's second point is "ongoing effects that last until the user .. stops paying FP".
Clearly you "stop paying FP" for the entire 59 seconds between payment intervals, so the implication here is probably "and your use expires".
Which would mean the condition of termination (stop paying FP) only kicks in at the end of the interval, like with magic spells, as seen in their Sorcery adaptations.
Meaning costs fatigue (or trigger, or limited use, or requires attribute roll) should not be capable of immediate switchoffs, just voluntary 1-minute expiration periods where they switch from Always On to Always Off due to voluntarily not spending FP, being exposed to the trigger, or making the attribute roll.
*this could make it advantageous to allow Switchable for these: to allow for immediate switch-offs rather than being locked in for the full 1 minute of use.
The -10% version of Costs Fatigue would have more immediate "switchoffability" due to the 1 second interval coming up sooner. That's a major advantage to it.
==Bio-Tech==
BT214
:Switchable is unnecessary if an advantage was limited with Costs Fatigue (p. B111), Emergencies Only (p. B112), Limited Use (p. B112), or Trigger (p. B115); such abilities are effectively switchable by default.
This conflicts with the design used in H79
==Powers==
GURPS Powers:
*pg 81 covers Switchable Body Parts
**Jason Levine clarifies in https://web.archive.org/web/20180122220021/http://forums.sjgames.com/showthread.php?t=63086&page=2 this makes them go away completely
*pg 109 lists it as an enhancement.
*pg 153 lists 2 required criteria which define a switchable attribute.
#The first is a list of 2 either/or criteria
##"it’s possible to switch the advantage on and off with a free action or a maneuver" (absent Always On)
##has Switchable or Usually On
#The second is a list of 3 options:
##effects which last until user turns off
##effects which last until concentration stops
##effects which last until FP payment stops (unclear if it applies to HP too)
Power-Ups 4 page 17 lists it as a +10% enhancement for non-switchable advantages.
==Quotes==
===Kromm===
http://forums.sjgames.com/showthread.php?p=250004&highlight=switchable#post250004 on 5 June 2006
:Powers is pretty clear on this . . . disadvantageous forms of "switchability" don't necessitate Switchable.
(only while conscious for example)
http://forums.sjgames.com/showpost.php?p=289977&postcount=2 references Powers 154 on 8 September 2006
:The only switchable abilities activated or deactivated with a free action are Mind Shield, attacks with Aura, and switchable advantages that work instantaneously thanks to Reduced Time. The user must switch these on or off at the start of his turn.\
http://forums.sjgames.com/showthread.php?p=1160048 in 2011:
:As has been explained often: Switchable is only needed if you lack modifiers that limit duration anyway. If you have Costs Fatigue, Limited Use, Maximum Duration, Takes Recharge, Trigger, etc., then you get the "use" specified by that modifier (usually a minute, except for Maximum Duration) and then the ability switches off. The values of these sorts of modifiers would be -10% more severe if this weren't assumed.
http://forums.sjgames.com/showpost.php?p=1397186&postcount=64 in 2012
:Certain limitations restrict length of usage, in effect establishing "uses." Some of these come in denominations as trivial as -5% or -10%. Examples include Costs Fatigue (-5%), Costs Hit Points (-10%), Limited Use (-10%), Maximum Duration (-5%), and Trigger (-10%). In such cases, adding Switchable, +10% would result in a 0% or even a +5% modifier, meaning there would be no cost savings and possibly a cost premium for a less-useful ability, which would clearly be unfair. Thus, all abilities with such modifiers are already switchable by dint of paying FP or HP, initiating a use, expending a trigger substance, etc. If they weren't, then not only would the cost be unfair, but also they would sit around, sucking up uses, FP, or whatever, because they couldn't switch off . . . a massive limitation, not a -5% to -10% one!
:The only error is that Maximum Duration shouldn't bother with "switchable." That text made it in from the Third Edition source, and isn't correct. 
:Also, one legalistic note for the lawyers: Debating whether PK and/or myself are correct or in error in our forums posts, and proposing to submit errata to resolve the issue if you disagree with us here, misconstrues the errata process. Our clarifications in these forums are de facto real-time errata responses, and canon. When stuff arrives via the errata form, we make exactly the same rulings, typically linking or pasting our forums responses for the errata coordinator to adapt, to save time. Thus, if you get an answer here, you have the final, official answer. There's no higher court – just a much slower one.
==See also==
*Active abilities
Category:Enhancements