10 Days of Gifting Question

So, with the birthday celebration of League (which I am very excited for) what happens if I miss a day? I know that there will be at least one day when I cannot play the game, so I am gonna lose out on one of those gifts?

The site says not to worry, but I am generally curious about how long the reward period is really for because the site makes it seem like even if you miss a day you can still get every reward. Is this true?