Please do not get your items very wet! Leather is a porous and natural material, it soaks up water, softens, and then never returns to its original state. It can handle some water and sweat exposure but the more frequently it does, the quicker the item will break down, age, and in general change.

The only item you really need is Duff’s Leather Dressing. It is inexpensive, a little goes a long way, seriously the best stuff on the market. You can use it on your boots, saddles, anything leather. It is amazing! And a sweet old fella developed it; you can purchase at the links below.
DUFF'S DRESSING

To clean – typically a lightly damp rag or sponge will wipe away any dirt. No need to scrub vigorously. If you have mud or too much dirt, a little bit of saddle soap can be used. Try to think about washing your face when you clean your leather item, not washing your mud boots.

Then follow with a little bit of Duff’s Leather Conditioning oil if it is very dry.

Otherwise, without even cleaning, Duff’s Leather Dressing can be wiped gently to lift dirt, then apply a few times to moisturize. These two items will not affect the color of the leather. If you use olive oil or neatsfoot, you will severely darken the leather, which is fine if that’s the goal, I do not recommend it for my work.
DUFF'S OIL