diff --git a/include/o3tl/lru_map.hxx b/include/o3tl/lru_map.hxx
index 42cb932786b0..859617e5d988 100644
--- a/include/o3tl/lru_map.hxx
+++ b/include/o3tl/lru_map.hxx
@@ -166,10 +166,10 @@ public:
     typedef list_iterator_t iterator;
     typedef list_const_iterator_t const_iterator;
 
-    // a size of 0 effectively disables the LRU cleanup code
     lru_map(size_t nMaxSize)
-        : mMaxSize(nMaxSize ? nMaxSize : std::min(mLruMap.max_size(), mLruList.max_size()))
+        : mMaxSize(nMaxSize)
     {
+        assert(mMaxSize > 0);
     }
     ~lru_map()
     {
@@ -182,7 +182,8 @@ public:
 
     void setMaxSize(size_t nMaxSize)
     {
-        mMaxSize = nMaxSize ? nMaxSize : std::min(mLruMap.max_size(), mLruList.max_size());
+        mMaxSize = nMaxSize;
+        assert(mMaxSize > 0);
         checkLRUMaxSize();
     }
 
diff --git a/o3tl/qa/test-lru_map.cxx b/o3tl/qa/test-lru_map.cxx
index edc9d7e1bf98..c99a803b3163 100644
--- a/o3tl/qa/test-lru_map.cxx
+++ b/o3tl/qa/test-lru_map.cxx
@@ -27,7 +27,6 @@ public:
     void testLruRemoval();
     void testCustomHash();
     void testRemoveIf();
-    void testNoAutoCleanup();
     void testChangeMaxSize();
     void testCustomItemSize();
 
@@ -38,7 +37,6 @@ public:
     CPPUNIT_TEST(testLruRemoval);
     CPPUNIT_TEST(testCustomHash);
     CPPUNIT_TEST(testRemoveIf);
-    CPPUNIT_TEST(testNoAutoCleanup);
     CPPUNIT_TEST(testChangeMaxSize);
     CPPUNIT_TEST(testCustomItemSize);
     CPPUNIT_TEST_SUITE_END();
@@ -295,24 +293,6 @@ void lru_map_test::testRemoveIf()
     CPPUNIT_ASSERT_EQUAL(size_t(0), lru.size());
 }
 
-void lru_map_test::testNoAutoCleanup()
-{
-    o3tl::lru_map<int, int> lru(0);
-    CPPUNIT_ASSERT_EQUAL(size_t(0), lru.size());
-    lru.insert({ 0, 0 });
-    lru.insert({ 1, 1 });
-    CPPUNIT_ASSERT_EQUAL(size_t(2), lru.size());
-    lru.insert({ 0, 0 });
-    CPPUNIT_ASSERT_EQUAL(size_t(2), lru.size());
-
-    int i = 0;
-    for (auto& rPair : lru)
-    {
-        CPPUNIT_ASSERT_EQUAL(i, rPair.first);
-        ++i;
-    }
-}
-
 void lru_map_test::testChangeMaxSize()
 {
     o3tl::lru_map<int, int> lru(3);
diff --git a/vcl/source/font/fontcache.cxx b/vcl/source/font/fontcache.cxx
index b98d1bb644cc..9a87d02bcda2 100644
--- a/vcl/source/font/fontcache.cxx
+++ b/vcl/source/font/fontcache.cxx
@@ -88,7 +88,7 @@ bool ImplFontCache::IFSD_Equal::operator()(const vcl::font::FontSelectPattern& r
 
 ImplFontCache::ImplFontCache()
     : mpLastHitCacheEntry( nullptr )
-    , maFontInstanceList(0)
+    , maFontInstanceList(std::numeric_limits<size_t>::max()) // "unlimited", i.e. no cleanup
     // The cache limit is set by the rough number of characters needed to read your average Asian newspaper.
     , m_aBoundRectCache(3000)
 {}