We do not need "for" when we use verb "last", but we can transfom such sentences into Present Perfect and then we can use "for". For example: he has been writing for two hours. BUT His writing lasted two hours. :)
that's a great explanation
Eveline.I've learned something.
Both can be used:
e.g.The ​exam lasted an ​hour and a ​half.
The ​drought lasted for several ​months.
They say the ​snow will last until the end of next ​week.