If you make very few changes to your plugins or widgets, you should be able to use the same critical CSS for months, meaning manually-generated CSS can be most cost-efficient for some clients.
If you are regularly changing or adding functionality, however, we highly recommend either (a) subscribing to a retainer with us, which allows us to check your speed results periodically and make updates as requested, or (b) using a plugin that can auto-generate your critical CSS.
While we’ve found that auto-generated critical CSS can be buggy, there are three services that attempt to do it:
- LiteSpeed, a plugin available to specific hosting environments
- WP Rocket, a paid plugin
- Autoptimize + Critical CSS, a £7/mo service
With options #2 and #3, we often recommend compromising by leaving the theme stylesheet render-blocking, then deferring all other styles. This prevents the need for maintaining critical CSS but may still have a small impact on PSI scores.