I was recently asked questions to this effect and here is my answer:

There is no single right answer to this. Every person is different including possibly during different stages of their lives.

To start answering the question, I would suggest you begin exploring your own circadian rhythm. See Wikipedia link below. And ask yourself:

  • When do I naturally wake up?
  • When do I naturally feel tired?
  • Do I take naps during the day?
  • When am I mentally fresh?

It is important to keep in mind that there is studying and there is remembering. Studying when you are tired is going to be less effective than studying when you are mentally fresh.

Also consider your environment – when and where do I find it easy to study? Are there times when it is more conducive to studying?

And equally importantly when you study what. Doing subject A at 7am in the morning may work better than subject B but that is ultimately up to you.

Just keep in mind that hours are not created equal. 7am in the morning is not the same as 7pm at night. In one instance, we may be just out of bed and in the other we may have lived a busy distracting day. Something to keep in mind!