By decomposing tasks, we can follow best practices for both project management and continuous delivery.
A well-worn principle of continuous integration is that developers should check in changes to the trunk every day. 
Meanwhile, a common project management practice is to chunk work into six-hour tasks. , 
We can combine these two best practices by working on tasks that can be developed in the range of four to eight hours.
If you don't think a task can be reduced to six hours, more or less, try harder. Perhaps a fresh approach to the task is needed so that developers do not go heads-down for days on end.
You can make excuses, or you can make progress.