As a developer, I often get to this point where at the end of the day I finish a big task and still have approximately 30 minutes to go.
The problem is that 30 minutes are not enough time for me to code anything, and if I start coding the very start of a task I know that I will struggle to continue it the next day while losing the context and will have to re-read the code, which will lead to me losing time.
But to focus on the professional problem, I don't want to slack off at work for so much time and staying there doing nothing during 30 minutes just seems absurd.
How do I deal with the "30 minutes remaining" issue?
EDIT : To explain why it's not a duplicate, the trouble is not about "what to do when the systems are down at work ?" or "what to do when I have nothing to do?" but "what to do when you arrive close to the end of the day and don't have the time to start a new task ?"