Before you discovered the magic of Timeline Genius, you may have used Excel or other spreadsheets to organize your timelines. If you find you miss having the grid lines to delineate between items, you can easily add those in to your PDFs.
When you're logged in to My Timelines, click on the dropdown of your company name in the top right corner.
Select "Yes" for "Show grid lines on PDF timelines".
Click "Update" and refresh any timeline preview you may have open. Voilà!