At The Master’s Seminary, one of the required classes for every student is a class on prayer.  From the seminary’s inception until this year, I believe that it has been taught by Dr. Rosscup (who does a mean Columbo impersonation, and writes Western novels under the pen-name of Jim Ross.)  What follows are his musings on Paul’s words in 1 Thessalonians 5:17, "Pray without ceasing…"

 
The verse in I Thessalonians 5 does not mean to pray absolutely all the
time, 60
seconds per minute.  This would leave no time for the myriad other things we
should do in God’s will.  We do need to do the things we pray about–be thinking
about safety in driving, studying,
counseling, speaking, asking or answering questions, eating, listening to a
piano number, on and
on.

        So what does it mean? 
Paul has more the idea of praying without allowing sin stops to our
praying, time outs from a life devoted to God’s will, to prayer about people and
things as these become relevant, or urgent.  Frequency
is involved, yes.  The
life can be one of prayer even in taking care of the many other things, for
God’s Word, His passions, and His concerns laid on our hearts in prayer can
pervade all other things.   It can influence, shape, fragrance in our
witness, study, attitudes in
driving, dependence on God in speaking, and the like (cf. Phil. 4:6,"in
everything, by prayer . . .").   When free from a given privilege in serving
God, such as leading a Bible study, and talking with others, our minds can fly
quite spontaneously to God as the needle on a compass points north.