Hello! Thanks for reading my very first post on this site!

All of you have been so much help to my planning! Thank you!
A friend of mine recently asked me if i was doing the unity candle or the sand... I honestly had no idea what either of those were until she asked. My question is.. Do I HAVE to do these? Is it something that shouldn't be left out, llike the cake or something? Or can I get away with not doing it?
HELP!