Over here in Malaysia, we do the same thing. If the new leather upholstery is too damn costly, we then have it sprayed by a professional upholstery sprayer. Have tried it many times, but there are a few pointers here. If the leather is worn and hardened with cracks all over, spraying will not help. It will look good for a short time, and will start chipping soon enough. It will then look worst then before. However, if the leather is still supple/soft but faded/discoloured (as it happens here often due to the tropical heat), then spraying will definitely help in the long run.

H Mayer
Malaysia
89' E34 520i Auto