diff --git a/build-sbx.sh b/build-sbx.sh
index f7e8258..435b479 100755
--- a/build-sbx.sh
+++ b/build-sbx.sh
@@ -83,6 +83,69 @@ prompt_component() {
     done
 }
 
+select_workspaces() {
+    # Namerefs let this helper read and write the caller's arrays by name.
+    # The source array stays unchanged so the displayed menu remains useful.
+    local -n available_workspaces="$1"
+    local -n selected_workspaces="$2"
+    local selection selection_part index
+    local valid_selection
+    declare -A selected_indices=()
+
+    printf 'Existing workspace directories:\n'
+    for index in "${!available_workspaces[@]}"; do
+        printf '  %d) %s\n' "$((index + 1))" "${available_workspaces[index]}"
+    done
+
+    while true; do
+        read -r -p 'Workspaces to reuse (a for all, n for none, or numbers such as 1, 3): ' selection || exit 0
+        selection="${selection//[[:space:]]/}"
+
+        # `a` reuses every path, while `n` deliberately starts with no
+        # inherited paths and leaves manual additions to the next question.
+        if [[ "$selection" == a ]]; then
+            selected_workspaces=("${available_workspaces[@]}")
+            return 0
+        fi
+        if [[ "$selection" == n ]]; then
+            selected_workspaces=()
+            return 0
+        fi
+
+        # Treat the numeric selection as a set so duplicate numbers are safe.
+        selected_indices=()
+        valid_selection=true
+        IFS=',' read -ra selection_parts <<< "$selection"
+        for selection_part in "${selection_parts[@]}"; do
+            if [[ "$selection_part" =~ ^[0-9]+$ ]]; then
+                index=$((10#$selection_part))
+                if ((index < 1 || index > ${#available_workspaces[@]})); then
+                    valid_selection=false
+                    break
+                fi
+                selected_indices[$index]=1
+            else
+                valid_selection=false
+                break
+            fi
+        done
+
+        if [[ "$valid_selection" != true || ${#selected_indices[@]} -eq 0 ]]; then
+            printf 'Please enter a, n, or valid workspace numbers from 1 to %d.\n' \
+                "${#available_workspaces[@]}"
+            continue
+        fi
+
+        selected_workspaces=()
+        for ((index = 1; index <= ${#available_workspaces[@]}; index++)); do
+            if [[ ${selected_indices[$index]:-} == 1 ]]; then
+                selected_workspaces+=("${available_workspaces[index - 1]}")
+            fi
+        done
+        return 0
+    done
+}
+
 cleanup_temporary_directory() {
     # EXIT traps run after `main` returns, so a variable declared local inside
     # `main` is no longer available. `${tmp:-}` also keeps nounset from
@@ -130,6 +193,7 @@ main() {
     local base_sandbox_name next_version selected_sandbox
     local -a current_workspace_paths=()
     local -a workspace_paths=()
+    local reused_workspaces=false
 
     if [[ "$build_from_scratch" == true ]]; then
         # Keep the three name components separate so common combinations are
@@ -162,6 +226,15 @@ main() {
                 <<< "$sandbox_json"
         )
 
+        if ((${#current_workspace_paths[@]} > 0)); then
+            select_workspaces current_workspace_paths workspace_paths
+            if ((${#workspace_paths[@]} > 0)); then
+                reused_workspaces=true
+            fi
+        else
+            printf 'The selected sandbox has no workspace directories to reuse.\n'
+        fi
+
         # A name ending in -v<number> is versioned. Strip that suffix and
         # increment it; an unversioned source starts at version 1.
         if [[ "$selected_sandbox" =~ ^(.*)-v([0-9]+)$ ]]; then
@@ -181,7 +254,7 @@ main() {
     if [[ "$build_from_scratch" == true &&
         ( "$sandbox_prefix" != 'finmas-gmbh' || "$sandbox_suffix" == 'private-api' ) ]]; then
         workspace_paths=("$HOME/docker-sbx/empty")
-    else
+    elif [[ "$build_from_scratch" == true ]]; then
         workspace_paths=("$HOME/Documents/git")
     fi
 
@@ -196,8 +269,14 @@ main() {
         printf '%s\n' "${current_workspace_paths[@]}"
     fi
 
-    # Additional paths are appended rather than replacing the default mount.
-    if ask_yes_no 'Do you want to add additional workspace directories?'; then
+    # Additional paths are appended rather than replacing reused paths.
+    local additional_workspace_prompt
+    if [[ "$reused_workspaces" == true ]]; then
+        additional_workspace_prompt='Would you like other workspaces added?'
+    else
+        additional_workspace_prompt='Do you want to add additional workspace directories?'
+    fi
+    if ask_yes_no "$additional_workspace_prompt"; then
         local workspace_path
         while true; do
             read -r -p 'Additional workspace path (press Enter when finished): ' workspace_path || exit 0