Well, how much sugar do you usually add to your macaroni and cheese?

Because the formal name for condensed milk is sweetened condensed milk, and more than half of what's in that can is sugar. Clearly you do not want to add sweetened condensed milk to your macaroni and cheese.

The use of evaporated milk in macaroni and cheese is an indication that your recipe is a little old-fashioned. The additional fat in evaporated milk keeps it from curdling, where low-fat or even whole milk would quite likely curdle during baking.

We have found a delicious recipe that combines the old-fashioned use of evaporated milk with a very modern approach to cooking it on the top of the stove. If you omit the bread-crumb step, you can produce this macaroni & cheese as quickly as you can prepare a processed boxed version.