The thing is brake pads are pretty cheap, and are fairly quick and easy to replace. Fuel these days is getting more and more expensive. I presume the fuel use comes from having to rev the engines up to operate the cooling fans. The airlines have the same issue, using reverse thrust on landing increases brake life, but uses more fuel and increases engine wear, as well as being noisy. Rising fuel costs coupled with increasing noise restrictions mean that planes rarely use more than idle reverse when landing, other than in wet conditions, which has no effect on fuel use or engine life. It's only real effect is to direct some of the thrust from the idling engines forwards, slightly aiding stopping. The A380 was actually not intended to have thrust reversers, but for certification did have to have them fitted, but only on the inner engines, and some smaller planes don't have them.
It's also true with road vehicles too. When I was learning to drive I was told to slow down on the brakes, not the gears, as it's cheaper and easier to replace brake pads than clutches. Even more true on Diesels as they don't actually have engine braking (unless specifically modified for engine braking). Engine brakes on diesels have the problem of being noisy (saw a coach today that must have had engine braking from the amount of noise it was making when slowing down).
Err that is not correct, big use is made of engine braking on diesel powered trucks, using exhaust brakes. a Diesel engine is a very high compression engine and as such is very good at 'engine braking', i've worked with and driven diesel driven trucks, mobile cranes, cars for over 25yrs. if you do an HGV(LGV) test you'll be taught the importance of engine braking and using the gears to slow you down,
to save your brakes, brakes get very hot during long descents and as such the braking retardation reduces the hotter they get, hence why you use the gears and the high compression of the engine to help keep your speed under control ;o)
On aircraft all airliners are fitted with reverse thrust, these days with high fuel prices it is used less than before, but it is used on almost ALL landings with exception to the early birds at LHR.
On the A380 reverse thrust was only fitted to the inboards because of the risk of ingestation of all sorts of debris near the edges of some runways and also it simply wasn't required as the thrust from just 2 of the large turbofan engines was more than enough to slow down the big bus, it was also always intended to have them fitted.
As for wear and tear the amount of time reverse is in use is nothting for a modern turbofan engine, as an aside it is the thrust from the Fan that provides the 'reverse' thust on a modern engine not the hot jet flux this continues to provide 'forward' thrust even with revers engaged ;o).
Modern turbofan engines provide nearly 85-90% of their thrust form the 'cold' Fan and 10-15% from the 'hot' jet flux ;o)
