Examples:

• How long have you been here in Boston?
• How long have you been here?
• How long have you been here? - I arrived at 8:30 am.
• You speak English very well. How long have you been here in the States?
• Sorry I'm late. How long have you been here? - Only five minutes.
• How long have you been here? - I've been living here for ten years.
• We really like living in this city. - Isn't it great? How long have you been here?
• How long have you been here? - We arrived at the hotel on Saturday night, so three days.
• I'm sorry I'm late. How long have you been here? - We've been waiting for only five minutes.