I dunno if your boots are old, but there are some products that deepen the colour of leather garments if they've been weathered. I use one such product
on my leather jacket and boots all the time to keep them looking brand new. If your leather boots are red, but they look faded, applying this stuff to them will pull the colour below the surface back to the surface to give the leather the deeper colour it once had. This stuff is inexpensive and effective. After a couple of days in adverse weather the darker finish might wear off, but you can recondition your boots with it to get the colour back within mere hours. Just don't apply this stuff to any suede leather, because it can and will ruin it.