Using LAMBDA avoids repititions by putting a range in LAMBDA call like this
LAMBDA([name, …], formula_expression)(range) and subtitite the range in the rest of the formula_expression with a name, in this case x or multiple names [name, ...].
Imagin having a range repeated 5 or more times, and that range is a long formula output, see this example
Using one name : x
The Old way
=SUM(B2+2+B2+5)
The new way using lambda
=LAMBDA(x, SUM(x+2+x+5))(B2)

Using multiple names: x,y
The Old way
=SUM(B2+2+B2+5)-B3*B3
The new way using lambda
=LAMBDA(x,y, SUM(x+2+x+5)-y*y)(B2,B3)

Common errors
You may encounter this error.
Error
Function LAMBDA should be followed by a call containing the actual values.
you probably wrote it like this
LAMBDA([name, …], formula_expression)
It should be like this
=LAMBDA([name, …], formula_expression)(range1,...)
=LAMBDA(x,y, SUM(x+2+x+5)-y*y )(B2 ,B3 )