4 years of physical cruft is something. Gunk deep in the keyboard, tired fan bearings, HD wear- it all adds up to more risk of data loss. That may be a random r

4 years of physical cruft is something. Gunk deep in the keyboard, tired fan bearings, HD wear- it all adds up to more risk of data loss. That may be a random reboot or data corruption. One or two days of lost work is generally more expensive than a new machine.