diff --git a/Rich/RichFutureUtils/include/RichFutureUtils/RichMirrorFinder.h b/Rich/RichFutureUtils/include/RichFutureUtils/RichMirrorFinder.h
index 215b57534e903ef0791cc5f74a884f55ef66d8f4..3163d366d86458b32cd8f26b6c787f9039eec968 100644
--- a/Rich/RichFutureUtils/include/RichFutureUtils/RichMirrorFinder.h
+++ b/Rich/RichFutureUtils/include/RichFutureUtils/RichMirrorFinder.h
@@ -267,18 +267,25 @@ namespace Rich::Utils {
         /// Combine two (scalar) x,y indices in a single one
         [[nodiscard]] ScalarIndex xyIndex( const ScalarIndex ix, //
                                            const ScalarIndex iy ) const noexcept {
+          assert( ix < NXBINS );
+          assert( iy < NYBINS );
           return ( NYBINS * ix ) + iy;
         }
         /// Combine two (SIMD) x,y indices in a single one
         [[nodiscard]] typename SIMDIndices::IndexType xyIndex( const typename SIMDIndices::IndexType& ix, //
                                                                const typename SIMDIndices::IndexType& iy  //
                                                                ) const noexcept {
+          assert( all_of( ix < SIMDIndices::IndexType( NXBINS ) ) );
+          assert( all_of( iy < SIMDIndices::IndexType( NYBINS ) ) );
           return ( SIMDIndices::IndexType( NYBINS ) * ix ) + iy;
         }
 
       public:
         /// Access the mirror for a given combined xy index (Scalar)
-        [[nodiscard]] MirrorNum get( const ScalarIndex ixy ) const noexcept { return ( *this )[ixy]; }
+        [[nodiscard]] MirrorNum get( const ScalarIndex ixy ) const noexcept {
+          assert( ixy < size() );
+          return ( *this )[ixy];
+        }
         /// Access the mirror for a given set of (x,y) indices (Scalar)
         [[nodiscard]] MirrorNum get( const ScalarIndex ix, //
                                      const ScalarIndex iy ) const noexcept {
@@ -289,6 +296,7 @@ namespace Rich::Utils {
         /// Access the mirror for a given xy index (SIMD)
         [[nodiscard]] SIMDIndices get( const typename SIMDIndices::IndexType& ixy ) const noexcept {
           // gather SIMD lookup
+          assert( all_of( ixy < SIMDIndices::IndexType( size() ) ) );
           return ( *this )[ixy];
         }