You can take it during cycle for gynecomastia issues by blocking estrogen receptors in the breast. Post-cycle it will help restart your natural testosterone production by acting on receptors in the brain.
If you aren't having (or have never had) gyno problems, then there's no need for it on-cycle. If you're really worried and still want to use it on-cycle as a precaution, you can start with 10 mg/day unless you still develope breast issues and feel you need more.