Usually, they last about 2-4 months, depends on how much you use them. I only use it about twice a week and it lasted 4.
1.75 US cups equates to 414mL
That is p That is about 0 .772 of a cup.
14 fluid ounces is about 414mL
215 ml is just under 1 US cup (0.90875186 US cups)