Show you Chinese culture...  In China,we have much tradition.For example,we have Spring Festival.On that day,we wear our new clothes.Families will have a get-together.It is very important.On that day,we exchange our best wishes.
  一切顺利  万事如意 can be used between freinds and relatives.
 寿比南山 身体健康 can be used between your grandparents.Certainly,saying  to old people is both right.