Upholstery dyeing

I have not ever had it done, but I have seen it done on one of the automotive related television shows.
If the leather is prepared properly, the dye should last for the life of the seat.
One thing to be aware of, most "leather" seats are not completely upholstered with leather. Typically, the part that you sit on is leather, and the sides and back are upholstered with vinyl.

I suppose that it will largely depend on the skills of the person doing the re-dyeing, that will determine the quality of the job done.

Re-upholster or get seats that are the color you want. It'll cost the same or less and you won't have to worry about a bad prep job or ruining clothes or anything if it rubs off.

I have had great luck dying interiors with SEM dye.

I dyed the entire interior of my 68 Barracuda from medium blue to black. That was 18 years and 100,000 miles ago. The door panels, visors, dash pad and all the plastic are still looking great. The seats the dye held up every where except the welting on the driver's side that required touching up once per year. The seat covers started tearing along the stiching after about five years (original to the car) so I did replace them with new covers but the dye never gave up.

Dave