Being that there are hundreds of shoes that come out every year, it’s no shocker that it’s daunting to choose a pair for yourself. Maybe you’re just starting out running, or maybe they don’t make the shoe you like anymore, or maybe you want to switch it up to change your style or prevent injury.

Luckily, despite a plethora of people saying “your need stability” or “you should go minimalist,” choosing a running shoe is actually very easy: Choose the one that’s most comfortable.

That’s not a cop out, either. That’s what the science says. This study from 2015 found that runners who selected their shoes based on comfort had lower injury rates and more efficient oxygen consumption. Now let’s look at the factors that impact the so-called “comfort filter”.

Weight

Lighter and heavier runners have different needs, especially as companies work to make shoes lighter and foams less dense. If you’re taking a sole and having someone who weighs 140lbs (64kg) and another who weighs 190lbs (86kg) both run in it, you can have different feelings from each of them. A denser sole may make the lighter runner think it feels like a brick, while the heavier runner loves the impact protect it gives. Similarly, an airy sole could be loved by a lighter runner, but the greater crushing force exerted by the heavier runner might make it feel like there’s no cushion at all.

Construction

The other primary aspect of avoiding injury when selecting a shoe is not picking anything that changes your running style too significantly. This means you want to avoid going directly from a bulky traditional shoe to a very minimalist one and vice versa. Luckily, your “comfort filter” will help choose something that’s within your body’s acceptable range.

Uses

Running might just be one part of your fitness program. If you’re also in the in the gym, you might be thinking about gym shoes. A pair that’s flatter, firmer, and has more lateral support. But if you can only get one shoe, the average running shoe generally adapts better to weight training than a training shoe adapts to running. In this case, you want your running shoe to be on the firmer side (most Hoka shoes are too squishy), avoiding any model that has a lot of space, like Nike Zoom models or some Mizuno Wave shoes. The Brooks Revel, New Balance Zante, and ASICS Roadhawk are great, inexpensive options that bridge the all-purpose gap.