fixing door drift
I had the house built 12 years ago the drifting only began a year or two ago. Prior to that they stayed put so I think they were hung properly. I am sorry to hear they have to be rehung.
The best check for this is to take a four foot level and take a reading on all three sides of the frame and the top(2 foot level). Then take the same reading on the door itself. If you can take a reading on the floor also. All readings should be true i.e. level. Where a non-leveling reading occurs will determine exactly where the problem exists.
If the framework is not true then the door will need to be rehung.
If the door is not true then the problem may lie with the hinges or the door itself.
If the floor is not true, leaning in the direction of the door swing, then you have some type of settling problem. I hope this clarifys it a little better for you. SORRY!!!