diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index e25b825a1..ca376c673 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -144,6 +144,8 @@ You'll need to update these every now and then when you change something in the
 yarn run critical
 ```
 
+You can temporarily disable critical path optimizations by loading it with `?nocrit=1`, eg, `https://devhints.io/?nocrit=1`.
+
 ## Critical path JS
 
 There's JavaScript that's included inline in every page. It's entrypoint is:
diff --git a/package.json b/package.json
index 8d787198b..d865510e0 100644
--- a/package.json
+++ b/package.json
@@ -26,7 +26,9 @@
     "critical": "node _support/critical.js",
     "dev": "run-p dev:webpack dev:jekyll",
     "dev:webpack": "webpack --watch --colors -p",
-    "dev:jekyll": "bundle exec jekyll serve --safe --drafts --watch --port $PORT --incremental",
+    "dev:jekyll": "if [ -f _site ]; then run-s dev:jekyll:incremental; else run-s dev:jekyll:initial; fi",
+    "dev:jekyll:initial": "bundle exec jekyll serve --safe --drafts --watch --port $PORT --incremental",
+    "dev:jekyll:incremental": "bundle exec jekyll serve --skip-initial-build --safe --drafts --watch --port $PORT --incremental",
     "test": "jest",
     "test:all": "run-s test lint",
     "lint": "standard -v",