Теория:

When and how to use FOR and SINCE in Present Perfect sentence:
FOR describes the duration of an action
 
FOR + A period of time
  • for 5 minutes
  • for 8 hours
  • for 2 days
  • for 4 weeks
  • for 6 months
  • for 3 years
  • for a long time
  • for ages
Example:
He has studied in Bangalore for 3 years.
He has lived here for 20 years.
They have been at the hotel for two weeks.
SINCE tells us when an action started
 
SINCE + A point in time
  • since 8 o'clock
  • since Monday
  • since last week
  • since August
  • since 2014
  • since I was 7 years old
Example:
It has rained since 9am.
We have learnt English here since 2010.
He has lived here since 2012
Ram has worked here since 2007.