How to pronounce 不必 in Cantonese (7 out of 8):

當日為咗避免不必嘅爭執
And that was to avoid unnecessary arguments.

Cantonese Sentence Breakdown

當日 dong1 jat6
on that day
為咗 wai4 zo2
(preposition) for; because of; in order to; for the purpose of; so as to; so that
避免 bei6 gyun3
avoid
不必 bat1 bit1
(verb) No need
koi3
indignant
generous
to sigh (with emotion)
爭執 zang1 zat1
dispute