Today marks the first day of Lent, when tens of thousands of Christians give up something they enjoy.
It is seen as remembrance for the time Jesus was said to have spent fasting in the desert.
A recent study found that the most popular things to give up include alcohol, social networking and coffee - with school and chocolate topping the poll.
Other big ticket items on the Twitter Lent Tracker include swearing, sweets, fast food, sex and sarcasm.
But how likely are you to succeed?
Psychologist at BWell Clinic in Dublin, Alison Keating, told Newstalk Breakfast going off things cold turkey might not be the best option.
"It's part of our binging culture that people will give up drink for the 40 days - like people doing it before November, before Christmas - but then an almighty binge happens"
"So perhaps it's better to go into the idea of more moderation, rather than this kind of 'all or nothing' thinking - that really can get people into trouble sometimes".
"It's useful to cut down on things, but if people are like 'that's it, I'm off drink completely', the mind psychologically sort of goes into depravation made".