It's not possible to separate the question from opinion without turning it into an entirely different question.

How long do you spend... ?

This portion makes the answer entirely dependant on who is being asked. Some people may spend their entire careers working on a "look", while others are more whimsical.

... shooting a single look?

What counts as a "single look"? -- What camera settings are allowed to change? Can the lens change? Can the subject change? Can the pose change? Can the environment change?

Answers to above questions may (again) be entirely personal to the writer (opinion).

Further, does post processing matter? Depending on the answer, the entirety of a photoshoot could be considered a "single look" or not. At the extreme, every single frame could be differentially processed into a different "look", and the answer could be as short as the shutter speed for each of those frames.

It's not possible to separate the question from opinion without turning it into an entirely different question. I am unable to discern a reason for the question beyond discussion. There is no objective answer.

How long do you spend... ?

This portion makes the answer entirely dependant on who is being asked. Some people may spend their entire careers working on a "look", while others are more whimsical.

... shooting a single look?

What counts as a "single look"? -- What camera settings are allowed to change? Can the lens change? Can the subject change? Can the pose change? Can the environment change?

Answers to above questions may (again) be entirely personal to the writer (opinion).

Further, does post processing matter? Depending on the answer, the entirety of a photoshoot could be considered a "single look" or not. At the extreme, every single frame could be differentially processed into a different "look", and the answer could be as short as the shutter speed for each of those frames.

It's not possible to separate the question from opinion without turning it into an entirely different question.

How long do you spend... ?

This portion makes the answer entirely dependant on who is being asked. Some people may spend their entire careers working on a "look", while others are more whimsical.

... shooting a single look?

What counts as a "single look"? -- What camera settings are allowed to change? Can the lens change? Can the subject change? Can the pose change? Can the environment change?

Answers to above questions may (again) be entirely personal to the writer (opinion).

Further, does post processing matter? Depending on the answer, the entirety of a photoshoot could be considered a "single look" or not.

It's not possible to separate the question from opinion without turning it into an entirely different question.

How long do you spend... ?

This portion makes the answer entirely dependant on who is being asked. Some people may spend their entire careers working on a "look", while others are more whimsical.

... shooting a single look?

What counts as a "single look"? -- What camera settings are allowed to change? Can the lens change? Can the subject change? Can the pose change? Can the environment change?

Answers to above questions may (again) be entirely personal to the writer (opinion).

Further, does post processing matter? Depending on the answer, the entirety of a photoshoot could be considered a "single look" or not. At the extreme, every single frame could be differentially processed into a different "look", and the answer could be as short as the shutter speed for each of those frames.