used to emphasize the importance or desirability of the quality or thing specified
1986 - Patrick Leigh Fermor - Between the Woods & the Water - He had a passion for limericks, the racier the better.
better the devil you know
it's wiser to deal with an undesirable but familiar person or situation than to risk a change that might lead to a situation with worse difficulties or a person whose faults you have yet to discover.
This phrase is a shortened form of the proverb better the devil you know than the devil you don't know.
better late than never
It's preferable for something to happen or be done belatedly than not at all.
better safe than sorry
It's wiser to be cautious and careful than to be hasty or rash and so do something that you may later regret.
Apparently the expression is quite recent in this form (mid 20th century) - better be sure than sorry is recorded from the mid 19th century.
1998 - New Scientist - The meeting is to be commended for taking a better safe than sorry attitude and drawing up a baseline list of measures to be put in place when disease
the better to
so as to
1986 - Peter Mathiessen - Men's lives - Francis ran both motors with their housings off, the better to tinker with them.
get the better of
win an advantage over someone
defeat or outwit someone
go one better
narrowly surpass a previous effort or achievement. narrowly outdo another person.
no better than you should be = no better than you ought to be
regarded as sexually promiscuous or of doubtful moral character
This phrase dates back to the early 17th century. Used typically of a woman, it is now rather dated.
1998 - Spectator - She's no better than she ought to be. (British mothers of my generation often used that enigmatic phrase. They would use it about female neighbours of whom they disapproved or women in low-cut dresses on television.)
your better half
your husband or wife – humorous
seen better days = known better days
be in a worse state than in the past
have become old or worn-out or shabby.
so much the better
It is better for that reason.
so much the worse
It is worse for that reason.
1995 - Guardian - If you can get a tropical fruit juice, so much the better.