How to know when to use middle term splitting in factorisation?

well after factorization u will get the quotient which r 3 terms u should use it there and it also depends upon question and marks

There are two conditions to use middle term splitting in factorisation.

Whenever you have a quadratic equation (an equation whos maximum power of x is 2)

For example: x²+4x+4.

Also, you should look at the equation and see if you can find anything in common in it.

x²+4x+4, here we can see x appears two times, 4 appears two times, 4 is also a multiple of two.

there are so many things in the above equation that can be factorised.

Hence, you can use middle term splitting in factorisation.