If you know someone well and it's a personal and informal communication, then absolutely use abbreviations.
Ọ bụrụ na ị maara ndị mmadụ nke ọma, na ọ bụ nkwurịta okwu onwe onye na nke na-ezighị ezi, mgbe ahụ, jiri nkwonkwo abbreviation mee ihe n'ụzọ zuru ezu.