Christ had long prayers and probably many short prayers. We are told that Christ 3 times prayed about one hour on the night they took him to be our sacrifice
Mark 14:34-37 (KJV)
And saith unto them, My soul is exceeding sorrowful unto death: tarry ye here, and watch. 35 And he (Christ) went forward a little, and fell on the ground, and prayed that, if it were possible, the hour might pass from him. 36 And he said, Abba, Father, all things are possible unto thee; take away this cup from me: nevertheless not what I will, but what thou wilt. 37 And he cometh, and findeth them sleeping, and saith unto Peter, Simon, sleepest thou? couldest not thou watch one hour?
I generally pray whatever is on my heart to pray which may be short or long. IMHO I don't think the time spent is as important as heartfelt sincerity and the constant nature of prayer in our lives.
cp