One of the greatest benefits of being a part of the WordPress community – is the access to the hundreds of thousands of existing plugins. A site owner can easily go from a vanilla site to something with a lot of functionality in a matter of minutes. On the same note – having access to all these plugins can easily cause more harm than help. Example: I recently worked with someone who was having problems with upgrading their site to the latest version of WordPress. I figured this would be a 30 minute task. After logging in and seeing they had over 60 plugins – 40+ which required upgrades – the task quickly grew.
By keeping everything up to date is important – but I would also like to stress keeping a lean version of your site is equally important. If you need a certain custom functionality – take into consideration the server resources, time for updates/debugging, etc. versus what you really get from it. Debugging 1 plugin is manageable, debugging 10 plugins is a task, debugging 40 plugins is insanity. Also – if you decide that a plugin is just not working the way you expected – delete it and forget about. There is no reason you need to keep plugins that you do not need around. By keeping these files around – it also takes up valuable resources that could be better used elsewhere.
If you are looking for a fast and secure web site (who isn’t?) remember to keep it simple. Custom functionality is great – but don’t forget to think about the cost.