David Carnoy, executive editor of CNET, a technology review web site, recommends replacing your desk top and laptop computers every four years unless your use is at a very basic level. In that amount of time, technology advances will dictate a hefty upgrade. Even if you are savvy enough to upgrade your old computer yourself, it will likely cost as much to do it as it would to buy a new computer. The same is true with laptops, which are much more complicated than desk tops to upgrade. From When to Replace Common Household Items by Kelly B. Grant, www.smartmoney.com.