1. it is helpful to have the contribution or advise of a second person rather than working independently
'Can I help?', 'Absolutely, two heads are better than one'.
When you say 'two heads are better than one', you are implying that having two people working on a task is more advantageous than one person. This is an idiomatic expression that you will often hear used in conversations where collaboration, group work or group thinking is encouraged. You will hear this in social and professional contexts, and it can even be used to respond to an offer of help.