"for a few days" or a "a few days"

Solution 1:

‘For’ adds a subtle sense of ‘duration’ - the passing of the time itself.

With ‘for’, we have a sense of ‘all of those moments passing’ - rather than just skipping to the end of the denoted time.

Consider:

• ‘She waited for five years, til he got out of jail’.

This has the subtle sense of her waiting every moment of the five years. Time drips by slowly. Her entire 5 years was ‘spent’ - on waiting for him.

• ‘She waited five years, til he got out of jail.’

Time does not drip by - we fast forward or skip to the five years later mark. She perhaps forgot about him, or saw somebody else for the 5 years, then whoops! He was back.

It is a very subtle difference. It might be used in creative writing, along with other cues, to tell us about how someone felt about time passing.