I had the rotors skimmed about 12 months ago and they were at their minimum usable thickness. I sourced a new aftermarket set from EBay. Overhaul is now done, very happy about the results as the brake efficiency has improved with less pressure on the brake lever.
Issues I had were:
1. I Could not get the retaining circlip off the brake master cylinder, I had to grind down the tips of the circlip pliers I purchased as they would not fit in the holes. The first set I bought had a right angle but would not reach into the circlip. I was also unable to get a hone small enough as the master cylinder was 15 mm in diameter and the smallest one I could get from the auto shops was 19 mm. I ended up using a piece of dowel and some emery paper to roughen up the cylinder to help the new seals to seal.
2. One of the pistons in the right side caliper would not come out. The manual suggests using compressed air and G clamp on the moving piston, I did this and was still unable to remove the piston. I ended up reinstalling the caliper without getting the piston out. Next time I change the front tyre I will use the hydraulic pressure of the master cylinder to push out the piston. I buffed up all the pistons I could get out with the wire buff on my grinder and cleaned all the gunk from inside the calipers.
3. Break bleeding took ages as I had trouble getting all the air out. I bought a car break bleeding kit a while ago and this came in very handy, if I did not have it I don't think I could have got the job done.
I would suggest if your brakes are getting hard a good clean will make a big difference.