Leather is a good string to have to your bow, I think you would struggle to make a living from just doing leather but when it's combined with the other cleaning it fits in nicely.
Craig says he can't stand cleaning leather, I love it, much easier and less messy that fabric.
I normally have a leather suite to clean or repair most weeks, though not every week.
Just did one this week (Mon) it had a 6" tear in the upper side cushion of a navy chair, right on the creases. I told the customer that I couldn't guarantee a perfect result, but it would be an interesting challange!
It was! Not perfect but quite satisfactory and a mighty challange, I even got a good colour match on the filler, took me just over two hours to repair, she was delighted. It then turned out that it was destined for one of her holiday cottages, she's got 12 of them!
So from that initial leather repair I have now arranged to clean the first two cottage carpets in 2 weeks time and then she wants to look at planning in the remainder as required. So all in all a good result which I may not have got if I didn't clean/ repair leather.