Board Thread:General Discussion/@comment-35490863-20180504180518/@comment-1038387-20180504190430

That depends really what the template uses. If it's just one standard wikitext function, "[youtube.com/]" or something, it should be okay. Parser functions or DPL are a slightly different story, but even that doesn't impact load times. Seconds, maybe. We've got cover galleries that use hundreds of DPL templates, but the only issue it runs into is sometimes when saving the page.