If you are learning a new concept or technique, do not 'try it out' during special occasions like Christmas, weddings or birthdays. You have plenty of tim to test your skill, knowledge and gear any other day.
'Experimenting' and trying to get a certain effect during special occasions can and will result to some - or many - bad shots if you are not familiar with a technique yet. You wouldn't want once-in-a-lifetime moments to have awful pictures, would you?
I'd rather stick to more automatic or familiar settings and make sure that I capture the moment vividly.
How about you? Would you risk it? Would you risk having terrible photos of once-in-a-lifetime moments for a chance to get better shots?