"Most" companies in the USA are on a 5-year laptop replacement cycle because that's what the IRS set the MACRS depreciation schedule to for "consumer electronics" (really, category 00.12 in Table B-1 of Publication 946). Each year following the purchase they can write off the following on their taxes:

Year 1: 20%

Year 2: 32%

Year 3: 19.20%

Year 4: 11.52%

Year 5: 11.52%

Year 6: 5.76%

Why accountants are actually in charge of the rate at which laptops get purchased, instead of just the paperwork for the tax deductions caused by the rate of laptop purchases....I truly do not understand.