What slows down WordPress the most? (Our findings after analyzing hundreds of sites)

Hey everyone 👋

We've been building WP Multitool — a WordPress performance toolkit — and after analyzing hundreds of WordPress sites, we keep seeing the same performance killers over and over:

1. Unoptimized database queries
The #1 culprit. Plugins running queries without proper indexing, autoloaded options tables growing to 50MB+, and post_meta queries that scan entire tables. Most site owners have no idea these are happening.

2. Too many autoloaded options
WordPress loads ALL autoloaded options on every single page request. We've seen sites with 10MB+ of autoloaded data. Transients that never expire, abandoned plugin settings — it adds up fast.

3. Plugins doing work on every page load
Some plugins hook into every request even when they're only needed on specific pages. A contact form plugin running its scripts on your homepage? A gallery plugin loading on your blog posts? Classic.

4. Missing object caching
Running a WordPress site without Redis or Memcached means your database handles the same queries thousands of times per day. Adding object caching is often the single biggest performance win.

We built WP Multitool specifically to help developers diagnose these issues — our Slow Query AI Analyzer catches the database problems, and the Autoload Optimizer handles the options table bloat.

What's the worst WordPress performance issue you've encountered? Would love to hear from other WordPress developers what patterns you see in the wild.