ir en aumento, aumentar, grammar sentence pattern

Question

to increase = ir en aumentowhen do we use aumentar vs ir en aumento? when do we use 'en' + noun pattern? or rather when do we use 'ir`? is it a grammar pattern where 'ir' + ' en' + noun?

Accepted Answer

Hola Ashlyn
Ir en aumento is a set phrase meaning "to be increasing" - it's not a structure that we can apply to any noun. We sometimes also say the opposite: ir en disminución (to decrease) 
These are more idiomatic than the general verbs "aumentar" and "disminuir".
There are other expressions using ir de + noun or an adjective for example, but they have their own meaning, also very idiomatic, for example:
ir en serio

Vamos, ¿vas en serio?
Come on, are you being serious?

ir en paz

...y al final de la misa el cura dijo a los feligreses: "podéis ir en paz" 
...and at the end of the service the priest said to the parishioners: "go in peace"

I hope this helps.
Saludos