Depends how you value your gaming experience.
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Stuck on a level, boss, timed section, finding collectibles, or advancing the plot in a warranted direction? Use it, to any extent.
Are you still stuck but want to learn from and feel the thrill of discovery and the pangs of creating a course of action? Don't use it.
In terms of value for money, will a walkthrough devalue the price of a product? No, because the experience varies each time you play, and is not dependent on the pricing of the item in question.
Value your time instead because you don't have enough time in your busy schedule to devote to games, but want to advance the plot? Then use a walkthrough to complement the gameplay while keeping the spoilers as far away from you as possible.
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No one way to look at it, really. It's your gaming experience, not mine, so go with the flow and do what you wish!
-----
Stuck on a level, boss, timed section, finding collectibles, or advancing the plot in a warranted direction? Use it, to any extent.
Are you still stuck but want to learn from and feel the thrill of discovery and the pangs of creating a course of action? Don't use it.
In terms of value for money, will a walkthrough devalue the price of a product? No, because the experience varies each time you play, and is not dependent on the pricing of the item in question.
Value your time instead because you don't have enough time in your busy schedule to devote to games, but want to advance the plot? Then use a walkthrough to complement the gameplay while keeping the spoilers as far away from you as possible.
-----
No one way to look at it, really. It's your gaming experience, not mine, so go with the flow and do what you wish!