Computers can only be expected to last 3-5 years and 5 years is the maximum support life Microsoft gives to their software, plus 5 years extended support for resellers, so in total, the maximum support life for any given computer you can expect is 10 years. Let’s break this down in an example for you. Assuming the computers can actually last 10 years.
If you have 20 computers in your office, and you really want to push the most life out of them possible, and you don’t want to wait until the last minute like April 8th, 2014 when Microsoft discontinues support for Windows XP and Office 2003, you will need to get on a regular replacement schedule, whether they are still working fine or not. That’s the catch, if they are still working and you try to hang on to them, you will be screwing yourself by the time you hit the 10 year mark having to purchase a pile of computers at the same time.
So 20 computers, divided by 10 years, equals 2 computers per year. So every 6 months you should be replacing a computer. Replacing the oldest computer in line for replacement. This way the oldest computer you would ever have is going to be 10 years old. If you don’t want any computer older than 5 years, obviously cut that number in half so you are replacing 4 computers per year.
If you have a proper IT budget in place for realistic life span of computers as well as IT support, maintenance, etc. you will be having less surprises financially to keep your IT equipment up to date. With that said, don’t forget about printers, scanners, copiers, routers, and switches…