sorry it was early when i wrote it meant to say 100, 000hrs actually it nearer to 120 000hrs.
age is an important factor on all aircrfat maintenace ois carried out according to cycles (pressuristion) landing cycles hours flowna nd calender time.
fuselages have a time life like under carrage, ie a point in time or cycles were it can not exceed, unlike other items such as idg which are on condition, ie they break they get replaced
and for those interesetd there is an in between called condition monitoring which studeis the condition and removes the item befroe total failure as this would be cheaper to over haul eg tyres engines

