"œBeware of the scribes, who like to walk around in long robes, and love greetings in the marketplaces and the best seats in the synagogues and the places of honor at feasts, 47 who devour widows' houses and for a pretense make long prayers. They will receive the greater condemnation."
In point of fact, there are verses that also say pray without ceasing as well, such as 1 Thessalonians 5:17. Though, this may be said to be hyperbole, I don't think we should turn away from the spirit of the command. It is good to pray throughout the day off and on, and it is something I could improve upon.
I think the tenor of Scriptures, and verses such as Matthew 6:5-6 and Mark 12:38-40 warn against the perils of praying for the glory of men, or denigrating prayers into magical incantations that somehow seek favor with God by their preponderance of words or length. Likewise, it condemns sterile formalism and mechanistic prayers that are not sincere.
It's a matter concerning the heart and carries a deeper spiritual depth that cannot always be put under the microscope of exegesis so easily, but it is not hard to get a feel for what Scriptures convey on the matter nonetheless.
I think Christians at one time or another might face the dillema about the efficacy of their prayers in their thoughts, as well as how they approach the matter. It is an important point to ponder.
I can't see being able to pray for everything I need to pray for without praying for everything I need to pray for.
If I take into account just the things I should pray for - praise ot God, church, family, sanctification, marriage, mortification of sin, kings, rulers, work, evangleism, etc., I can't see prayer "regularly" being too short. Devotions in reading/studying and prayer should be a good time, but a hearty time. I think, then, if we are familiar with the Bible, and know all the things the Bible tells us to pray for (commands us) then prayer will be a longer time than a shorter time.