Not all automatic movements are equal… building choices by different brands generate different recharge systems, more or less efficient (meaning fast) in recharging the spring.
The only information given by the watch firms is the maximum lenght of the carge, and not the time needed to reach it.
The question “How long do I need to wear an automatic watch to keep it functioning?”, beyond depending on the activity of the wrist wearing the watch, cannot have a univocal answer. Yet…

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