Monotonic search space technique

How do we know that we have to use monotonic search cpace in a given question?
I understood the technique but find it difficult to infer which question are suitable for it?

@igarg145
hey
yr thode kafi typical questions hote h
binary search apply karne ke
vo agar kar lye to pata chal jata h
jaise square root


fir ekh monkey walla
and hacker block meh
book allocation painters problem
vo karoge na to thoda trend pata chal jayega
so u can easily make out
jaise bhaiya na video me h bola
3:00 min peh ki 0 -> kiisi quantity ke bech lie karte h solution
to uss case meh use karna h concept