Anything between now and never.
Unfortunately, there are no guarantees of a sale. Itch.io provides a platform but beyond that you have to market the game yourself. The majority of my games have no sales from itch.io members - the sales they do have were
- I had a promotion on another site and redirected people here;
- my friends that buy them - even though I'd give it to them for free - or in some cases did give it to them for free;
- when I put them on sale - long time ago before itch.io had this many games on it - I've had no luck with recent sales.