Prayer makes us strong from the devil’s scheme. Jesus even told the disciples on how to pray properly
Yes
Praying for a longer time makes us more connected and intimate with God, and we can grasp a deeper understanding on how He works mysteriously in our lives.
No
Jesus told us that prayers should not be too long but precise, pray with all your heart and not necessarily to repeat what you have to say. Before we can open our mouths to pray, He knows what we need.