In reply to Doug Arnold.

Hi Doug, the number of plugins itself is not a factor of performance. Theoretically, you could have 10,000 plugins running on your site without issue.

Only poorly written plugins affect site performance. If a plugin is affecting the performance of your site on a measurable level, then it was written incorrectly. Tools like P3 could be helpful in spotting the bad ones to save you the time and hassle of running benchmark tests on your own.

I shy away from using "kitchen sink" plugins that sport 100 features, 2 of which I actually want. These types of plugins are more likely to be written poorly because their scope has likely become too broad and they end up lacking a defined purpose.

Someone could say that by limiting the number of plugins on your site you are also decreasing the chance of accidentally using a bad plugin, but that's just an argument of probability, and in my opinion sets a false precedent.

Plugins are good. Use them often. Use them wisely. :-)