You can select (tick) Same day Catchup if you want to catchup websites earlier on the same day.
Say you have two websites for a Saturday:
If you start Firefox at say 9.00am, then:
- If, Same day Catchup is selected, then both websites (8.00am and 9.00am) will open.
- If, Same day Catchup is not selected, then only http://www.amazon.com 9.00am will be opened.