Waxed Roughout is a very low maintenance leather.
Most of the time, it won't need anything more than a brushing, with a standard horse hair shoe brush.
With more wear, you'll start to notice areas where the wax has fallen off, revealing the lighter-colored "hairy" nap of the roughout. Some people love this worn "patina" look and will let it be.
But if you prioritize protection and durability over cool looks, you'll want to rewax. To rewax these parts, first remove dirt and debris using a horse hair brush. Then, apply the wax.
The gold standard for rewaxing roughout is Venetian Leather Cream. This is used by Horween Leather Company to finish their famous waxed roughout product, Waxed Flesh. It comes as a thick liquid in a bottle, so it's easy to pour and apply. However, some people don't like that it has petroleum distillates (for a full discussion on this topic, see Does It Matter If Your Leather Conditioner Has Petroleum? | Stridewise).
If all-natural, non-toxic, and eco-friendly are your top priorities, we recommend Otter Wax Boot Wax instead. It comes as a solid in a tin, so it will take a bit more effort to apply. Having a heat gun or hot blow dryer will melt the wax and make it easier to work with, both in the tin before you apply, and on the leather itself after you apply.
If you prefer video instructions, the video below is a comprehensive guide to cleaning and rewaxing.