IRD prescribes 4 years as the useful life of PC and servers, and allows 30% annual straight line depreciation rate (Page 51 of IRD 265). Does it imply that we should keep our PC and network servers for 4 years?  No, it does not. How long we can keep a PC or server for depends on two questions.  Is it still fit for purposes in the 2nd, 3rd, 4th or even 5th year?  Can the equipment be re-deployed?  Obviously we wish to keep our equipment in use for as long as we can so that we can maximize the return on our investment.  We would like to suggest 2 concepts here for use.  Maximizing the use of a PC or server does not mean keeping it in service for as long as possible.  The correct definition is to use the piece of equipment to best serve the defined purposes of the company. Practically all people know the purposes of their own company but few are experts as well in computer technologies.  It is wrong to assume that a PC is a PC and that all PC sales people do not misrepresent.  Many people buy PC or servers as commodities and are not aware that there are other PC or servers that can are more stable, faster and better.  This is called fitness for purposes (FFP). There are also PC and servers that work seamlessly for 7 years such as those in use by Compucon.  High quality equipment produces less outage, needs less time to attend to and enhances productivity.  They are important for reducing the total cost of ownership (TCO) which, when coupled with FFP, maximizes the return on investment.  You can keep PC and servers for as long as 7 years if your requirements are pre-defined, you use top quality equipment and provide a good environment for them.