Your age.
Age or a balloon.
Age, the New Year, and space go up but never come down.
I'd say that's more of a true statement rather than an idiom. Prices never DO come down - they always go up.
your age
Your AGE!
Age
Stairs go up and come down as well.
Rain I beg to differ. Rain may come down, but accdording to the water cycle, the "rain" becomes rundown water, and eventually evaporates, therefore, rain does go up.
age
The years never go down addition your age and the time
An escalator. They're one-way devices. Either up or down.Another Opinion:Escalators ARE reversible!
a meteor how could u not know that