WordPress would not have the functionality it is known for without the over 20,000 free plus commercially available plugins that enhance the native functionality of the base installation software. These plugins offer enhancements, but at the same time pose risks to a stable and long lasting installation. Being that WordPress is an open source software, anyone with a computer and a free WordPress account can post in the WordPress repository.
This means that code will become part of your website and the only one to scrutinize its authenticity and compatibility is you or your WordPress developer. I have seen even entities posing as web development and marketing companies adding plugins that clearly would be a risk to the longevity of the web site. For the most part picking the best plugin is just common sense.
The number of positive reviews:
The number of positive reviews is a good indication on how the plugin performed as advertised, including incompatibility issues that were found in relation with other themes and plugins. The number is based on a 1-5 scoring, with 5 as the best,allowing registered WordPress users to rate their experience, documents and incompatibility issues. My personal belief is that any plugin with an overall score of under 4.0 does not belong on any site. There may be cases where it is impossible to avoid using plugins that fall below 4.0, but extreme caution should be taken.
The last time the plugin has been updated:
The last time a plugin has been updated is a good indication of the level the developer is willing to go to maintain the plugin software versus the latest versions of WordPress, as well as other incompatibility or security issues. I would say a good rule of thumb is that the plugin has been updated in the last few months. This can ensure that the plugin has been tested with the latest and more stable release of the WordPress software.
Total number of downloads:
The total number of downloads of the plugin is a good indication of its stability. A plugin with a million downloads will have a larger testing base, better qualified with the number of user reviews. The more popular plugins will make it to review sites that further increase the number of downloads. In addition, a larger number of downloads will allow for testing between more themes and plugins combinations. The total number of download is probably the first thing that I observe when looking at a plugin.
The version number of the plugin is a good indication of the frequency of updates. A plugin with a high version number has been upgraded more often than a lower one. This version is set by the developer and is updated and increased each time a new version is released to the repository. The higher the version number along with the last time that the plugin was updated will give insight into how active the plugin is be tested and updated.
The compatibility level is the level up to which the plugin is tested against. This will indicate “Compatible up to “X.X.X,” which will be the version of WordPress the plugin has been tested up against. Another indicator that falls in the same category is what version is required to run the plugin. I feel this number is less significant as WordPress should be constantly updated for stability and security.
All of the above factors play into whether a plugin is stable, secure and tested against the most current versions of WordPress. The person who is managing your site should be aware of this importance when selecting a plugin to enhance any functionality. A poor selection in this area can very likely compromise your WordPress site.