Jeremy's First Law of Continuous Integration:
If you check in very often and/or first, you can make merge conflicts be someone else's problem.
The Second Law:
If someone did sneak in a check in between two of your check ins then the merge problem will be small because the number of changes you've done will be small if you're checking in frequently.
The Law of Encouragement:
Point this out to your coworkers to make all changes between check ins as small as possible so that you don't waste half a day on merging.