I doubt this, I've done some branch-and-bound implementations in the past which searched recursively through a graph and it was crucial for speed to see if a partial solution was already calculated.

Some graph search algorithms avoid memoizing by ordering the input nodes (thus avoiding duplications) In aforementioned cases this wasn't possible at all!

update

for instance see wikipedia Dynamic_programming

The dynamic programming approach seeks to solve each subproblem only once, thus reducing the number of computations: once the solution to a given subproblem has been computed, it is stored or "memo-ized": the next time the same solution is needed, it is simply looked up. This approach is especially useful when the number of repeating subproblems grows exponentially as a function of the size of the input.