What causes yellowing on sneakers?

There are a few reasons your white shoes and soles might turn yellow over time, but the main reason is oxidation. In some cases, though, it might be because of something simple like dirt or because you aren't cleaning them correctly

How do you keep white sneakers from turning yellow?

To keep sneakers from yellowing, store them away from direct sunlight and keep them clean. Yellowing is mainly caused by oxidation, and oxidation is accelerated by dirt and sunlight.

Since yellowing mainly affects the midsole and outsole this answer is for those parts of the sneaker in particular.

Before we put away whichever pair we’ve worn on a given day make sure that at a minimum we’ve cleaned the outsoles and midsoles.

Depending on the kind of dirt that gets on your sneakers you’ll want to use different products. 

A great product for midsoles is the RENEWILL which is  a shoe cleaner kit brand

Let everything air-dry, and certainly don’t let your sneakers dry in the sun.

Once you get in the habit of cleaning your sneakers after each wearing, you’ll get more efficient at it and it will take less time.