Mergers of equal partners are rare and difficult to carry out.

All noble things are as difficult as they are rare

All excellent things are as difficult as they are rare.

This is like moving two elephants. No matter how well you move it, there's still tons of weight.

It makes a lot more sense for it to happen now.

The laser scanner measures the time it takes (to go) from the instrument to the wall. Then it computes the distance between the wall and the layers of paint.