diff --git a/common/font/outline_decomposer.cpp b/common/font/outline_decomposer.cpp
index 65cca8d1b3..257a1b13d9 100644
--- a/common/font/outline_decomposer.cpp
+++ b/common/font/outline_decomposer.cpp
@@ -160,6 +160,8 @@ bool OUTLINE_DECOMPOSER::approximateQuadraticBezierCurve( GLYPH_POINTS&       aR
     // cp0 = qp0, cp1 = qp0 + 2/3 * (qp1 - qp0), cp2 = qp2 + 2/3 * (qp1 - qp2), cp3 = qp2
 
     GLYPH_POINTS cubic;
+    cubic.resize( 4 );
+
     cubic.push_back( aBezier[0] );                                           // cp0
     cubic.push_back( aBezier[0] + ( ( aBezier[1] - aBezier[0] ) * 2 / 3 ) ); // cp1
     cubic.push_back( aBezier[2] + ( ( aBezier[1] - aBezier[2] ) * 2 / 3 ) ); // cp2
diff --git a/common/plotters/GERBER_plotter.cpp b/common/plotters/GERBER_plotter.cpp
index 71edaa6dd2..2779dc9a76 100644
--- a/common/plotters/GERBER_plotter.cpp
+++ b/common/plotters/GERBER_plotter.cpp
@@ -804,6 +804,8 @@ void GERBER_PLOTTER::Rect( const VECTOR2I& p1, const VECTOR2I& p2, FILL_T fill,
 {
     std::vector<VECTOR2I> cornerList;
 
+    cornerList.reserve( 5 );
+
     // Build corners list
     cornerList.push_back( p1 );
 
@@ -1526,6 +1528,8 @@ void GERBER_PLOTTER::plotRoundRectAsRegion( const VECTOR2I& aRectCenter, const V
     RR_EDGE curr_edge;
     std::vector<RR_EDGE> rr_outline;
 
+    rr_outline.reserve( 4 );
+
     // Build outline coordinates, relative to rectangle center, rotation 0:
 
     // Top left corner 1 (and 4 to 1 left vertical side @ x=-hsizeX)
diff --git a/common/plotters/PS_plotter.cpp b/common/plotters/PS_plotter.cpp
index b4d95bcdd5..8b0d18a908 100644
--- a/common/plotters/PS_plotter.cpp
+++ b/common/plotters/PS_plotter.cpp
@@ -144,9 +144,9 @@ void PSLIKE_PLOTTER::FlashPadRect( const VECTOR2I& aPadPos, const VECTOR2I& aSiz
                                    const EDA_ANGLE& aPadOrient, OUTLINE_MODE aTraceMode,
                                    void* aData )
 {
-    static std::vector<VECTOR2I> cornerList;
+    std::vector<VECTOR2I> cornerList;
     VECTOR2I size( aSize );
-    cornerList.clear();
+    cornerList.reserve( 4 );
 
     if( aTraceMode == FILLED )
         SetCurrentLineWidth( 0 );
diff --git a/common/plotters/plotter.cpp b/common/plotters/plotter.cpp
index 3ff5ad8a36..15ae6e6325 100644
--- a/common/plotters/plotter.cpp
+++ b/common/plotters/plotter.cpp
@@ -253,6 +253,8 @@ void PLOTTER::BezierCurve( const VECTOR2I& aStart, const VECTOR2I& aControl1,
     int minSegLen = aLineThickness;  // The segment min length to approximate a bezier curve
 
     std::vector<VECTOR2I> ctrlPoints;
+    ctrlPoints.reserve( 4 );
+
     ctrlPoints.push_back( aStart );
     ctrlPoints.push_back( aControl1 );
     ctrlPoints.push_back( aControl2 );
@@ -295,6 +297,8 @@ void PLOTTER::markerSquare( const VECTOR2I& position, int radius )
     std::vector<VECTOR2I> corner_list;
     VECTOR2I              corner;
 
+    corner_list.reserve( 4 );
+
     corner.x = position.x + r;
     corner.y = position.y + r;
     corner_list.push_back( corner );
@@ -326,6 +330,8 @@ void PLOTTER::markerLozenge( const VECTOR2I& position, int radius )
     std::vector<VECTOR2I> corner_list;
     VECTOR2I              corner;
 
+    corner_list.reserve( 4 );
+
     corner.x = position.x;
     corner.y = position.y + radius;
     corner_list.push_back( corner );
diff --git a/pcbnew/router/pns_optimizer.cpp b/pcbnew/router/pns_optimizer.cpp
index 31fa3eca6b..51d06b2c9e 100644
--- a/pcbnew/router/pns_optimizer.cpp
+++ b/pcbnew/router/pns_optimizer.cpp
@@ -820,7 +820,9 @@ OPTIMIZER::BREAKOUT_LIST OPTIMIZER::rectBreakouts( int aWidth, const SHAPE* aSha
     const SHAPE_RECT* rect = static_cast<const SHAPE_RECT*>(aShape);
     VECTOR2I s = rect->GetSize();
     VECTOR2I c = rect->GetPosition() + VECTOR2I( s.x / 2, s.y / 2 );
+
     BREAKOUT_LIST breakouts;
+    breakouts.reserve( 12 );
 
     VECTOR2I d_offset;