LoneW. - My only knowledge of TBO's is in association with a new product where conservative TBO's are set on day one and the manufacturer seeks to grow those as real world experience increases. I didn't realise that they could be reduced as a type aged.
I guess the gearbox designers are struggling with weight issues so how much metal goes into the vital components is clearly a critical part of the design. Well, here is one pilot that would beg the designers to put 15kg (my flight bag) of metal back into the gearboxes or any where else where margins have been pared to the bone.
G.