In the present perfect tense, “since” and “for” are used to indicate the duration of an action:
1. “Since”:
Refers to a specific point in time when the action began.
Examples:
I have lived here since 2010.
She has worked here since Monday.
2. “For”:
Refers to a period of time that the action has lasted.
Examples:
I have lived here for 10 years.
They have studied for three hours.
Tip: Use “since” for a starting point and “for” for a duration.