How do you say "off and on" in Italian
In English we can say that we do something "off and on," meaning, sporadically or occasionally. Is there an Italian equivalent?I study Italian off and on.
I write my novel off and on.
I am a vegetarian, off and on.

Question

How do you say "off and on" in Italian
In English we can say that we do something "off and on," meaning, sporadically or occasionally. Is there an Italian equivalent?I study Italian off and on. 
I write my novel off and on. 
I am a vegetarian, off and on.

Answer

I would pick from yhe following list:
a) in modo incostante
b) senza costanza ( = /non con costanza/ but direct meaning)
c) saltuariamente
d) in modo episodico
e) quando posso
There are different shades of meanings, if not clear, please ask again.

Answer

"a fasi/periodi alterni"
"un po' si e un po' no"
"incostantemente"
"non regolarmente"
"ogni tanto"

There is no general way to convey the meaning of "off and on", the best way is to build a periphrasis using the expressions above, or the ones suggested by the other users.

Answer

I think "ogni tanto" is the most common way to say this.

Answer

Ogni tanto is the most used.

Answer

In addition to the answers you have already had I say: "ad intermittenza".
For instance: Studio l'italiano ad intermittenza.