All of the above. I was told the products you use on your tack are not meant for the type of leather on your boots. A clean cloth for removing dust and grime and the occasional polish are really all you need.
For longevity of the leather, don’t wear the boots when you’re bathing your horse and avoid wearing them in muddy conditions. To have a shine that’s for real rather than just cosmetic, never ever apply polish of any sort on your boots when they’re dirty or dusty. I see this at horse shows all the time and I just cringe. But I wipe them down every time I get off my horse and, as much as possible, I wear boot protectors if I have to walk around in them and especially if I have to walk a course with my boots on. It also helps to understand that the part of the boot that makes contact with the horse will pick up oils from the horse not matter how clean the horse is. This will then attract more dust and grime. So you have to use some elbow grease to remove it. With properly clean and polished boots, all the other dirt and dust will wipe off easily.
I save my good boots for shows and they usually get only one polish per show. I thoroughly clean the boots with a barely damp cloth and apply polish (Kiwi) really rubbing it into the leather. I wear old thick socks so that I can use my fingers but not end up with horrible stains. I let the boots sit overnight and in the morning I use a soft shoe brush to brush them and bring out the shine. Seriously, I do this once for a five-day show. And I’ve had judges comment on how shiny my boots are.