Leo Varadkar (Dublin West, Fine Gael) | Oireachtas source

That can be done in respect of sunset clauses. When we reduced VAT for the tourism and hospitality sector, we indicated that it would only last for three years, although that was not written into the law. When there is a sunset clause, however, we always come under pressure to extend it anyway. I am not sure how effective they are. I would not have a sunset clause when it comes to exempting child benefit from income tax or exempting the sale of a family home from capital gains tax.

See this speech in context