diff --git a/.github/workflows/windows-nightly.yml b/.github/workflows/windows-nightly.yml
index 2d4dee96d..a67be5402 100644
--- a/.github/workflows/windows-nightly.yml
+++ b/.github/workflows/windows-nightly.yml
@@ -47,57 +47,60 @@ jobs:
 
     # declare/restore cached things
 
+    # stack's global package db, holding package indexes, our haskell deps, downloaded ghc
     - name: Cache C:\Users\runneradmin\AppData\Local\Programs\stack\
       uses: actions/cache@v1
       with:
         path: C:\Users\runneradmin\AppData\Local\Programs\stack\
-        # key: ${{ runner.os }}-appdata-local-programs-stack
-        #key: ${{ runner.os }}-appdata-local-programs-stack-${{ github.sha }}
         # which files signal a change in the global stack dir ?
-        # 'stack.yaml','stack.lock' should be included, but how
-        key:          ${{ runner.os }}-appdata-local-programs-stack-${{ hashFiles('*/*.cabal') }}
+        # **.yaml includes stack.yaml and */package.yaml, and hopefully no other changing yamls
+        # stack.lock should be included too, but how..
+        key:          ${{ runner.os }}-appdata-local-programs-stack-${{ hashFiles('**.yaml') }}
         restore-keys: ${{ runner.os }}-appdata-local-programs-stack-
-    - name: Cache C:\Users\runneradmin\AppData\Local\Packages\
-      uses: actions/cache@v1
-      with:
-        path: C:\Users\runneradmin\AppData\Local\Packages\
-        key: ${{ runner.os }}-appdata-local-packages
 
+    # stack's local bin dir (like ~/.local/bin)
     - name: Cache C:\Users\runneradmin\AppData\Roaming\stack\
       uses: actions/cache@v1
       with:
         path: C:\Users\runneradmin\AppData\Roaming\stack\
-        key: ${{ runner.os }}-appdata-roaming-stack
+        key: ${{ runner.os }}-appdata-roaming-stack-${{ hashFiles('**.yaml') }}
+        restore-keys: ${{ runner.os }}-appdata-roaming-stack-
 
+    # stack's local package dbs, for the project and each package
     - name: Cache .stack-work
       uses: actions/cache@v1
       with:
         path: .stack-work
-        key: ${{ runner.os }}-stack-work
+        key: ${{ runner.os }}-stack-work-${{ hashFiles('**.yaml') }}
+        restore-key: ${{ runner.os }}-stack-work-
 
     - name: Cache hledger-lib/.stack-work
       uses: actions/cache@v1
       with:
         path: hledger-lib/.stack-work
-        key: ${{ runner.os }}-hledger-lib-stack-work
+        key: ${{ runner.os }}-hledger-lib-stack-work-${{ hashFiles('hledger-lib/package.yaml') }}
+        restore-key: ${{ runner.os }}-hledger-lib-stack-work-
 
     - name: Cache hledger/.stack-work
       uses: actions/cache@v1
       with:
         path: hledger/.stack-work
-        key: ${{ runner.os }}-hledger-stack-work
+        key: ${{ runner.os }}-hledger-stack-work-${{ hashFiles('hledger/package.yaml') }}
+        restore-key: ${{ runner.os }}-hledger-stack-work-
 
     - name: Cache hledger-ui/.stack-work
       uses: actions/cache@v1
       with:
         path: hledger-ui/.stack-work
-        key: ${{ runner.os }}-hledger-ui-stack-work
+        key: ${{ runner.os }}-hledger-ui-stack-work-${{ hashFiles('hledger-ui/package.yaml') }}
+        restore-key: ${{ runner.os }}-hledger-ui-stack-work-
 
     - name: Cache hledger-web/.stack-work
       uses: actions/cache@v1
       with:
         path: hledger-web/.stack-work
-        key: ${{ runner.os }}-hledger-web-stack-work
+        key: ${{ runner.os }}-hledger-web-stack-work-${{ hashFiles('hledger-web/package.yaml') }}
+        restore-key: ${{ runner.os }}-hledger-web-stack-work-
 
     # actions
 
@@ -125,22 +128,22 @@ jobs:
         stack --resolver=lts --no-terminal install --ghc-options=-Werror --test
         #  --bench --no-run-benchmarks --haddock --no-haddock-deps
 
-    - name: Show stuff
-        # ls C:\Users\runneradmin\
-        # ls C:\Users\runneradmin\AppData\
-        # ls C:\Users\runneradmin\AppData\Local\
-        # ls C:\Users\runneradmin\AppData\Local\Programs\
-        # ls C:\Users\runneradmin\AppData\Local\Programs\stack
-        # ls C:\Users\runneradmin\AppData\Local\Programs\stack\x86_64-windows
-        # ls C:\Users\runneradmin\AppData\LocalLow\
-        # ls C:\Users\runneradmin\AppData\Roaming\
-        # ls C:\Users\runneradmin\AppData\Roaming\stack\
-      run: |
-        ls C:\Users\runneradmin\AppData\Roaming\local\bin\
-        ls C:\Users\runneradmin\AppData\Roaming\local\
-        ls D:\a\hledger
-        ls D:\a
-        ls D:\
+    # - name: Show stuff
+    #     # ls C:\Users\runneradmin\
+    #     # ls C:\Users\runneradmin\AppData\
+    #     # ls C:\Users\runneradmin\AppData\Local\
+    #     # ls C:\Users\runneradmin\AppData\Local\Programs\
+    #     # ls C:\Users\runneradmin\AppData\Local\Programs\stack
+    #     # ls C:\Users\runneradmin\AppData\Local\Programs\stack\x86_64-windows
+    #     # ls C:\Users\runneradmin\AppData\LocalLow\
+    #     # ls C:\Users\runneradmin\AppData\Roaming\
+    #     # ls C:\Users\runneradmin\AppData\Roaming\stack\
+    #   run: |
+    #     ls C:\Users\runneradmin\AppData\Roaming\local\bin\
+    #     ls C:\Users\runneradmin\AppData\Roaming\local\
+    #     ls D:\a\hledger
+    #     ls D:\a
+    #     ls D:\
 
     # run hledger-lib/hledger functional tests, skipping the ones for addons
     #- COLUMNS=80 stack exec -- shelltest --execdir -j16 tests -x /bin -x /addons