DURING and FOR

Study the following sentences:

Hizo mucho calor durante el verano. = It was very hot during the summer.
Mis tíos vivieron allí durante cinco años.= My uncle and aunt lived there for five years.
Durante la última media hora ha llamado cuatro veces. = He's phoned four times during the last half hour.
  Trabajaré en Washington (durante) cinco años. = I'll work in Washington for five years. 

   These examples prove that it is NOT a good idea to say durante = during or durante = for. NO -- it depends on the sentence!
   So what is the rule? The easiest way to understand this is to think about the question:

• If you ask HOW LONG...?, then use FOR. 

               You can stay for a few days. (How long can I stay?)

                I've known her for a long time. (How long have you known her?)

                She lived here for five years. (How long did she live here?)

• If you ask WHEN?, then use DURING.

                They met and fell in love during the journey. (When did they meet?)

                He died during the night. (When did he die?)

                The village was abandoned during the war. (When was the village abandoned?)

                I worked in a pizza restaurant during the summer holidays last year. (When did you work in a ..?)

   Two more tips (consejos):

•  During can almost always be replaced (sustituido) by IN. 
• If you use a number + a period of time, (three years, five months, ten weeks), you almost certainly need for.