"From time to time"

Translation: Od czasu do czasu

[SaraWie]

In what casu is 'czasu' here?

[SaraWie]

Haha, I meant case

[immery]

It can be only genitive

https://en.wikibooks.org/wiki/Polish/Prepositions_as_hints_to_declensions

https://pl.wiktionary.org/wiki/czas

[mihxal]

twice genitive