Estimate total hours needed to prepare for an exam.
Exam preparation is not one pass over the material. The first pass is the expensive one; each subsequent revision pass costs roughly half the previous, because you are refreshing rather than learning, so three passes total about 1.75 times the first pass rather than three times it. Multiplying by topic count gives the real total, and dividing by the days remaining is the reality check — anything above five hours a study day means the scope has to shrink or the start date had to be earlier.
Pass decay
Hours per topic = first pass x (1 + 0.5 + 0.25 + ...) for the number of passes
Schedule
Total = topics x hours per topic; per study day = total / weeks / study days per week
Because retrieval is faster than acquisition. Once the material is encoded, a pass is about strengthening recall and finding gaps, which is why spaced repetition works on short, frequent sessions rather than long re-readings.
For most exams, yes: learn, consolidate, then test under time pressure. Fewer than two leaves recall fragile; more than four tends to reread comfortable material instead of attacking the weak topics.