diff --git a/libs/ardour/session_click.cc b/libs/ardour/session_click.cc
index dd38b4ec75..bf90e1576e 100644
--- a/libs/ardour/session_click.cc
+++ b/libs/ardour/session_click.cc
@@ -124,6 +124,7 @@ Session::click (samplepos_t cycle_start, samplecnt_t nframes)
 		const samplepos_t end = start + move;
 
 		_click_points.clear ();
+		assert (_click_points.capacity() > 0);
 		TempoMap::use()->get_grid_with_iterator (_click_iterator, _click_points, samples_to_superclock (start, sample_rate()), samples_to_superclock (end, sample_rate()));
 
 		if (_click_points.empty()) {
@@ -310,6 +311,12 @@ Session::setup_click_sounds (Sample** data, Sample const * default_data, samplec
 		delete[] tmp;
 		sf_close (sndfile);
 	}
+
+	/* Overwhelmingly likely that we will have zero or 1 click grid point
+	 * per cycle. So this is really overkill. If it is too low, it just
+	 * causes RT memory allocation inside TempoMap::get_grid_with_iterator().
+	 */
+	_click_points.reserve (16);
 }
 
 void