Netbooks are cheaper, lighter and generally operate more slowly than an ordinary laptop -- but should their expected lifespan be shorter?That is the question Public Service Association (PSA) IS project manager Richard Finlay is asking after three of the six Hewlett Packard mini notebooks he purchased failed in less than 15 months. He met with HP and distributor The Laptop Company to formally complain and was later informed that the models he had purchased -- HP2140 and HP2133 -- were not expected to last beyond two years."The units purchased are essentially low-end models and as such the lifespan is only estimated to be 15-24 month," HP business development manager Gill Brown wrote in an email to Finlay.He is disappointed with her reply. "HP's netbooks are not the cheapest on the market. My users accept that to get the convenience of the small and lighter equipment there is a trade off in performance. I don't accept that there should be a trade off in quality," he told Computerworld.