diff --git a/.github/workflows/gofmt.yml b/.github/workflows/gofmt.yml
index d96daed..770b0ec 100644
--- a/.github/workflows/gofmt.yml
+++ b/.github/workflows/gofmt.yml
@@ -2,23 +2,25 @@ name: gofmt
 on:
   push:
   pull_request:
+  schedule:
+    - cron: '1 1 1 * *'
 jobs:
   run_gofmt:
     runs-on: ubuntu-latest
     steps:
-    - name: checkout
-      uses: actions/checkout@v4
-    - name: set up go
-      uses: actions/setup-go@v4
-      with:
-        go-version: 'stable' # echo "go version" in the log
-    - name: run gofmt
-      shell: sh
-      run: |
-        files_with_format_issues="$( find . -name '*.go' -print0 | xargs --null --no-run-if-empty gofmt -l )"
-        echo 'files_with_format_issues:'
-        echo "${files_with_format_issues}"
-        num_files_with_format_issues="$( echo "${files_with_format_issues}" | grep --text --count '^./' || : )"
-        echo 'num_files_with_format_issues:'
-        echo "${num_files_with_format_issues}"
-        exit ${num_files_with_format_issues}
+      - name: checkout
+        uses: actions/checkout@v4
+      - name: set up go
+        uses: actions/setup-go@v4
+        with:
+          go-version: 'stable' # echo "go version" in the log
+      - name: run gofmt
+        shell: sh
+        run: |
+          files_with_format_issues="$( find . -name '*.go' -print0 | xargs --null --no-run-if-empty gofmt -l )"
+          echo 'files_with_format_issues:'
+          echo "${files_with_format_issues}"
+          num_files_with_format_issues="$( echo "${files_with_format_issues}" | grep --text --count '^./' || : )"
+          echo 'num_files_with_format_issues:'
+          echo "${num_files_with_format_issues}"
+          exit ${num_files_with_format_issues}
diff --git a/.github/workflows/markdownlint.yml b/.github/workflows/markdownlint.yml
index 49a3856..f446f27 100644
--- a/.github/workflows/markdownlint.yml
+++ b/.github/workflows/markdownlint.yml
@@ -1,12 +1,14 @@
 name: markdownlint
 on:
- push:
- pull_request:
+  push:
+  pull_request:
+  schedule:
+    - cron: '2 2 1 * *'
 jobs:
   run_markdownlint:
     runs-on: ubuntu-latest
     steps:
-    - name: checkout
-      uses: actions/checkout@v4
-    - name: Run markdownlint
-      uses: actionshub/markdownlint@main
+      - name: checkout
+        uses: actions/checkout@v4
+      - name: Run markdownlint
+        uses: actionshub/markdownlint@main
diff --git a/.github/workflows/shellcheck.yml b/.github/workflows/shellcheck.yml
index e1a15bc..3e68dde 100644
--- a/.github/workflows/shellcheck.yml
+++ b/.github/workflows/shellcheck.yml
@@ -1,13 +1,15 @@
 name: shellcheck
 on:
   push:
+  schedule:
+    - cron: '4 4 1 * *'
 jobs:
   run_shellcheck:
     runs-on: ubuntu-latest
     steps:
-    - name: checkout
-      uses: actions/checkout@v4
-    - name: run shellcheck
-      uses: ludeeus/action-shellcheck@master
-      with:
-        severity: style
+      - name: checkout
+        uses: actions/checkout@v4
+      - name: run shellcheck
+        uses: ludeeus/action-shellcheck@master
+        with:
+          severity: style