Amazon moved a subset of its servers back to a five-year depreciation life

Straight-line depreciation divides cost by life. At six years a server expenses about 16.7 percent of its cost annually; at five years it expenses 20 percent, a fifth more per year for the same box ^[1]. Shortening the life of equipment already in service does not restate the past. The remaining book value is spread over the shorter remaining life, so the charge rises from the change date forward. Equipment pulled out before its schedule ends leaves book value with nowhere to go, and it lands in one period. Amazon booked roughly $920 million in accelerated depreciation and charges tied to retiring equipment early ^[2].

Add the two disclosed pieces of the 2025 hit and you get about $1.3 billion of reported operating profit given up by revising an estimate downward ^[2].

Whether five years belongs in anyone else's model depends on what the fleet holds. Microsoft's fiscal 2026 capital expenditure came to about $145.3 billion, and roughly $91.1 billion of it, about 63 percent, went into short-lived assets led by processors, GPUs and network gear ^[9]. Run one year of those purchases through both lives: six years gives an annual charge near $15.2 billion, five years near $18.2 billion, a difference of roughly $3.0 billion a year ^[3]. That calculation assumes straight line, no salvage value, and every asset in service on day one. None of those hold for a real fleet, which is why the figure is a bound and not a forecast.

A useful life is a management estimate, and one extra year changes the profit printed on the page ^[12]. As the dev.to account has it, at a small company an accountant notes the change and moves on, while at the scale of one of the largest compute fleets a single year moves serious money ^[14]. The traffic had been going the other way: Alphabet raised server life from four years to six in January 2023 and certain network equipment from five to six, cutting depreciation expense by $3.9 billion and lifting net income by $3.0 billion ^[5], and Meta extended most of its servers to five and a half years in 2025, reducing depreciation by about $2.9 billion ^[6].

The dev.to review of the filings says they do not separate the money that adds new computing capacity from the money that buys back capacity a company already had ^[13]. Both land in the same capital expenditure line. Microsoft's cash outlay for property and equipment went from about $23.9 billion to $115.9 billion over four years, close to five times ^[10][4].

For five years to be the right input somewhere else, the hardware has to sit in the same class as the servers Amazon moved, and it has to be replaced for the reason Amazon gave in the filing: technology moving faster, "particularly in the area of artificial intelligence and machine learning" ^[1].