Calculating how to layer on clothing for maximum comfort while venturing outside can be a tricky equation.

There are lots of variables, like unknown or changing weather conditions and activity levels that can range on a given day from strenuous boot-packing or snowshoeing to long sedentary chairlift rides or winter camping.

Everybody’s different, too, with different comfort and exertion levels, so there’s no one-size-fits-all answer to the layering question. Lucky for us, we can leave our Number 2 pencils at home, because this is a trial-and-error sort of thing. Once you figure out the layering options that work best for you, your time outdoors becomes that much more enjoyable.

Today’s baselayers are highly breathable, which allows them to wick moisture and makes them perhaps the most important piece of your arsenal when it comes to pure temperature regulation. The right baselayer complements the rest of your layering system, making the whole system as versatile as possible.

Though it might seem counterintuitive, thicker doesn’t always mean warmer. Baselayers come in different weights and thicknesses, and many people prefer the thin and lightweight variety. Most modern baselayers are meant to have a close fit without being overly tight.

Here’s an overview of some different layering options, some study material to help you make the most of your layering decisions.