Need for db.collections.close after CRUD operations

Best practice is to close MongodB after each CRUD operations or else I will get memory leak over time?

Often I do not see db.close so my question is that is it absolute must?

Unlike “typical” web applications which often open and close the database around a CRUD operation, the Meteor server runs continuously (all things being equal) and the connection to the database remains open all the time. If you were to close the connection to the database, you would close it for everybody!

Thanks Rob, because I followed MongodB University and they showed db.close after a CRUD operation.