For casual bakers, exact precision using grams can help... Or it might not matter at all. You'd need to have everything else be as precise for it to matter. Are you weighing your eggs? Do you adjust based on the humidity of the air? Do you know all of the hot spots in your oven and is the thermometer accurate?

It's science, but ya gotta realize you arent baking a sphere in a vacuum ya know?

At least a gram is a gram is a gram everywhere in the world!

> Are you weighing your eggs?

Yes, always.

I don't know what its like where you are, but where I am you can get eggs either in mixed packets, or sorted by size.

So where I am, 1 egg != 1 egg unless you weigh it.

It doesn't matter for soufflé's or meringues. But for everything else you'll have problems if you use random sized eggs.

> Do you adjust based on the humidity of the air?

Absorption capability of flour tends to be more important.

> Do you know all of the hot spots in your oven

Put it in fan mode and reduce the temperature. Hot spot problem disappears.

A nice packed cup can fit like 50% more than a very loose cup. It's a much bigger issue "exact precision".

For eggs, as long as you know the right category of egg it'll be within 10% and that's a lot less of a worry.