For this sort of dough you may need e.g. 1.8g of yeast (that's the actual quantity I used for the last dough I made). It depends on how much flour you make, of course, but pizza doughs with long fermentation use minute amounts of yeast. If you use 1.6g or 2.0g instead of 1.8g, your pizza may be ready twelve hours too soon or too late.

I bought a second kitchen scale to deal with the minute quantities, since my old one is accurate to only 1g.