When should we play tournaments and when to play cash games ? How to decide ?

When to play tournaments and when to play cash games ? How can we decide ? Or it's random depends on the mood ? Please guide.

For me if you wish to play for occasional fun with quick withdrawals in terms of small profits (depending on the stakes as well) then go for cash games!
But if you wish to make a name for yourself and build a huge bankroll (fortune) then there’s no alternative to tournaments!

I usually play cash in between tournaments.

You should try both and see which one suits you. These are two differeng games