"Too many cooks spoil the broth" suggests that having too many people working on one task can lead to confusion and failure. The common saying "there's no time like the present" recommends engaging in work as soon as possible, rather than putting the work off.
Sayings such as these are often called proverbs, which are short sayings that describe a belief. Proverbs become popular because they express a thought that is widely accepted as valid or true.
"Necessity is the mother of invention" refers to the idea that many new technologies are created in response to some human need. "Bite the bullet" means one should engage in an unpleasant, but necessary, task. "A penny saved is a penny earned" suggests that that a person could accumulate more wealth by saving money instead of spending money. "Familiarity breeds contempt" concisely explains that being constantly exposed to a particular thing creates annoyance with said thing. "A chain is only as strong as its weakest link" means that a one unskilled worker or team member could bring down the entire group's performance. "Actions speak louder than words" is a reminder that what a person does is more important than what a person says he will do.