Both partners in a couple have individual bad habbits and flaws that they themself might not be aware of.
Not easy to leave one’s responsibilty of a sincere opinion (advice), and overdoing it might lead to frustration for a partner.
Would you want to delay your advice to the time when someone else embarrasses him/her by pointing out the bad habbit ? As they say " The cruelest lies are told in silence".
Or would you feel that this would give an impression that you are very picky about his/her faults. You point one finger at others and three of your own fingers are pointing at yourself.
What wisdom would you adopt to maintain a balance ?