Computers older than 3 years are not cost effective

New computers can deliver better performance, improved features, and increased reliability over computers more than 3 years old. Maintenance costs of older computers can rise up to 1.5 times that of a new computer. Downtime also increases as computers age. A study done by Techaisle showed that downtime for computers older than 3 years was on average 10 hours/year compared to new computers at 7 hours/year. The study goes on to show that a small office with 5 PCs - 2 > 3 years old and 3 < 3 years old will spend $1500 more in maintenance costs than on office with all PCs < 3 years old. Newer software also produces benefits. Windows 7 has many benefits over its earlier versions. 

Consider your maintenance costs and downtime when you make the decision whether to fix that old computer or buy a new one!