Its a common problem on all cars with leather after a few years of use, the side bolster gets a lot of hammer getting i and out, and the studded pockets on denims dont help.

Dont think you can swap the seats across as the adjuster switches would then be on the inside and difficult to reach.

I use boot polish on mine a couple of times a year and it hides the small amount of wear on my drivers seat bolster.

There are also some DIY touch up and renovation kits on the net which are easy to use, I bought one for another car and it was supplied with dye perfectly matched based on the car model, it just sponged on after applying a cleaner, and then a top coat of polish was applied, everything is supplied in the kit and it wasnt expensive.

Try googling car leather restoration kits.