Prepositions of Time
For and since are both used to say how long something was. However, we use them with different time words.
We use for when we say the number of hours, days, months, etc. We also use it in expressions like "for ages" and "for a long time".
I'm going to live in France for 2 years.
I sat down for 5 minutes.
I've worked here for 3 months.
We use since when we say when something started (e.g. Tuesday, 2008, midnight). We only use since with perfect tenses - you can read more about them in my grammar pages.
I've lived here since October.
I'd known Sam since 1999.
We use during with nouns (e.g. the holiday, my party, the night). Sometimes it means for all the time, and sometimes it means for just a part of the time.
My grandmother worked in the USA during the war.
I heard a strange noise during the night.