Website maintenance is usually an overlooked aspect of owning a website and keeping a website up-to-date is very important. A website is never really finished being built, it is a process. Continuous improvement to a website will give you an edge over any competitor that hasn't kept their website current. 

Jakob Nielson, a top website usability specialist, says: 

"As a rule of thumb, the annual maintenance budget for a website should be about the same as the initial cost of building the site, with 50 percent as an absolute minimum.  Obviously, ongoing costs are even higher for news sites and other projects that depend on daily or real-time updates.  If you simply spend the money to build a glamorous site but do not keep it up to date, your investment will very rapidly turn out to be wasted. The Web currently changes so rapidly that a major redesign is needed at least once per year simply to avoid a completely outdated look and to accommodate changing user expectations.  Additional maintenance is needed throughout the year to bring fresh content online, reorganize and revise old pages, and avoid linkrot." Needless to say, website maintenance is very important.