I see this kind of stuff at companies where only one or two developers work on a project, or the team working on it hasn't had much experience on other projects

I see this kind of stuff at companies where only one or two developers work on a project, or the team working on it hasn't had much experience on other projects. An example would be a company I worked for who ran a pretty standard LAMP setup but had never heard of memcached. Simply adding that reduced the database load by like 90%.