Kanji or kana for いってきます?


Should I use kanji or kana for the first and second verbs in いってきます? When each
verb is used individually there's usually kanji if I recall correctly, but I'm
wondering if it's changed for being used in a stock phrase, and if so whether
the first, second or both verbs use kana.




I would write it as 行ってきます, with きます in Hiragana, probably because the
きます([来]{く}る) is a subsidiary verb (補助動詞) here.




I would write it as 行ってきます, with きます in Hiragana, probably because the
きます([来]{く}る) is a subsidiary verb (補助動詞) here.

