Is there a standard energy consumption on the usage of Devil Fruit powers?

Question

Im on Episode 685, and while Captain Law runs out of energy after using his ability to deflect/slice about 4 meteors the size of the Sunny (rough estimate), I'm seeing this guy with Flamingo now controlling enough stone to be an actual mountain in a human shaped form, smashing his fists all over the place, with no apparent attempt at conserving energy.

So are some Devil Fruit powers just lucky, and allow infinite or a massive amount of usage, for example moving a mountain constantly for a hour or two, while others are extremely limited? Does it have nothing to do with the amount of work being done, for example?

In other words, is there any gauge or limit for the usage of all DF powers, or does it vary just completely randomly?

Answer 1

No, there isn't.

This answer is based on my observation throughout the series:

Paramecia Devil Fruits:

These fruits give the users a power that can affect their body, manipulate the environment, or produce substances. In general, Paramecia Devil Fruits are fruits that give their users powers other than transforming into natural elements, like Logias, or transforming into animals, like Zoans. (Source)

• The amount of energy required for the Devil Fruit user varies from one to another based on their power, with some requiring a good amount of energy while others requiring pretty less.

• Most importantly, I think the exhaustion arises from the level of concentration or the use of the fruit to its extreme, rather than from using the fruit's ability directly. My basis for saying so is that:

  Luffy expends that energy because he's doing hyper-physical activity, not because the fruit powers innately require energy as a source.

  Gear Second uses even more oxygen and energy, using up more food and causing Luffy to pant heavily. The increase in his metabolism causes him to be hungrier than usual or even have a paralysis type effect after prolonged use of it, like in the second fight with Rob Lucci, where Luffy was only able to lie on the floor.

  Essentially Luffy increases the blood flow by forcing more blood through his blood vessels thus increase his fighting ability. (Source)

  Similarly, Law does not get tired just by using "Room". What makes Law tired is the concentration it requires him to control the things in his "room".

  Furthermore, while Law can control everything within a particular area, if he loses his concentration on an opponent, then they can still move freely, as seen when Vergo was able to retrieve Law's heart while he was distracted. (Source)

Logia Devil Fruits:

Logia Devil Fruits allow a person to create, control, and transform into a natural element or force of nature, depending on the fruit. The user can transform partly, or completely. It is characterized by giving its user the ability to turn into a natural element or force of nature. (Source)

• These devil fruits are almost never tiring because the user doesn't have to expend themselves to use the basic powers of the fruit, ie, to convert to an energy/element. Neither have I ever seen a Logia user get exhausted after using his/her energy for a long time.

Zoan Devil Fruits:

This type of fruit allows the user to transform into another species and inter-species hybrid forms at will. Zoan types are especially effective in close combat. (Source)

• Like other devil fruits, using the Devil Fruit directly, ie, to convert oneself to convert to another species isn't exhausting. The way it's used determines the exhaustion level of the user.

  Physical powers granted are restricted to just the capabilities of the proportionate physical equivalent of the animal they are able to transform into. In hybrid form, these strengths of both species may be combined, but again seems to be just a mixture of both forms. While it is true that they enhance the strengths of the consumer, they rely primary on the consumers fighting skills and capabilities. (Source)

TL;DR: The devil fruits do not innately require energy as a source for their use and what makes the user tired is the way he/she uses it and their stamina also plays a huge part in it.