The length of the second half of the Tribulation Period is 1260 days.  The Lord comes to earth with His bride at the end of this period, and defeats those who oppose Him.  It is necessary to have 75 days to do two things.  30 days are needed to prepare the bride to rule with Christ.  They are assigned their positions where they will serve during the millennium.  Another 45 days are needed for Christ to judge the nations.  If you add all of these numbers the total comes to 1335 days.  Daniel 12:  12 says:  "Blessed is the one who waits for and reaches the end of the 1335 days."  Those who wait and reach the end will then be blessed by starting to rule and reign with Christ!  The abomination of desolation and the fleeing of Israel into the wilderness occurs at the middle of the Tribulation Period.  Believers have a marvelous  future waiting for them.
 
Wes K.