Be abit careful, sofas being sold as leather are often only leather faced and then plastic on sides and back, they will discolour at different rates and will soon look very poor.
Also, they are often made from split leather which is very thin. Unlike fabric, leather has no elasticity and so when it is stretched (by being sat on !!!!) it does not return to shape, it then folds over, the crease is sat on and then it splits. If you are on a tight budget, buy fabric if you want good value for money buy full skin leather, within a couple of years it will pay for itself.
Also, be careful of BI-Cast leather in sofas, Bi-cast is the equivelant of Leather papermache (particles of leather glued together) It is now illegal to call it leather in New Zealand and Australia and this is now spreading throughout the REAL Leather industry.
Before anyone asks, yes I do know about leather and wooden furniture, I have been technically involved in it for over 20years.