How to scale the mesh to the geometry size

Hi,

I have a quick question: if you mesh a 2D square geometry of size 'L' with a mapped mesh and a total of 'x' domain elements, what would be an appropriate scaling criteria for the mesh if I was to multiply the size of square by a factor of 2,3,4...? An obvious one would be to multiply the number of domain elements by the same factor I feel that would be probably too much and thus inefficient..

Thanks for your help