diff --git a/docs/tied_sequence.md b/docs/tied_sequence.md
index 0ef59fe..ab2a6a7 100644
--- a/docs/tied_sequence.md
+++ b/docs/tied_sequence.md
@@ -303,25 +303,29 @@ constexpr size_t size() const noexcept;
 constexpr size_t max_size() const noexcept;
 ```
 
-<!--
 ### reserve
 
 ```cpp
 constexpr void reserve(size_type new_cap);
 ```
 
+Available only if every sequences provide `reserve()`.
+
 ### capacity
 
 ```cpp
 constexpr size_type capacity() const noexcept;
 ```
 
+Available only if every sequences provide `capacity()`.
+
 ### shrink_to_fit
 
 ```cpp
-constexpr void shrink_to_fit() noexcept;
+constexpr void shrink_to_fit();
 ```
--->
+
+Available only if every sequences provide `shrink_to_fit()`.
 
 ## Modifiers
 
diff --git a/flat_map/tied_sequence.hpp b/flat_map/tied_sequence.hpp
index 9e72d52..12f30ca 100644
--- a/flat_map/tied_sequence.hpp
+++ b/flat_map/tied_sequence.hpp
@@ -471,10 +471,7 @@ class tied_sequence
     constexpr reference back() { return *std::prev(end()); }
     constexpr const_reference back() const { return *std::prev(end()); }
 
-    constexpr pointer data() noexcept((static_cast<void>(sizeof(std::declval<Sequences>().data())), ..., true))
-    {
-        return detail::tuple_transform([](auto& c) { return c.data(); }, _seq);
-    }
+    constexpr pointer data() noexcept { return detail::tuple_transform([](auto& c) { return c.data(); }, _seq); }
 
     constexpr const_pointer data() const noexcept(noexcept(std::declval<tied_sequence*>()->data())) { return const_cast<tied_sequence*>(this)->data(); }
 
@@ -497,13 +494,11 @@ class tied_sequence
 public:
     constexpr size_t max_size() const noexcept { return detail::tuple_reduction([](auto&&... c) { return std::min({c.max_size()...}); }, _seq); }
 
-#if 0 // TODO
     constexpr void reserve(size_type new_cap) { detail::tuple_reduction([new_cap](auto&... c) { (c.reserve(new_cap), ...); }, _seq); }
 
     constexpr size_type capacity() const noexcept { return detail::tuple_reduction([](auto&... c) { return std::min({c.capacity()...}); }, _seq); }
 
-    constexpr void shrink_to_fit() noexcept { detail::tuple_reduction([](auto&... c) { (c.shrink_to_fit(), ...); }, _seq); }
-#endif
+    constexpr void shrink_to_fit() { detail::tuple_reduction([](auto&... c) { (c.shrink_to_fit(), ...); }, _seq); }
 
     constexpr void clear() noexcept { detail::tuple_reduction([](auto&... c) { (c.clear(), ...); }, _seq); }
 
diff --git a/test/tied_sequence.cpp b/test/tied_sequence.cpp
index a148618..4d65bd8 100644
--- a/test/tied_sequence.cpp
+++ b/test/tied_sequence.cpp
@@ -650,14 +650,13 @@ TEST_CASE("capacity", "[capacity]")
         REQUIRE(ts.max_size() > 0);
     }
 
-#if 0 // TODO
     SECTION("reserve/capacity")
     {
         flat_map::tied_sequence<std::vector<int>, std::vector<int>> ts;
         REQUIRE(ts.capacity() == 0);
         REQUIRE(ts.size() == 0);
         ts.reserve(10);
-        REQUIRE(ts.capacity() == 10);
+        REQUIRE(ts.capacity() >= 10);
         REQUIRE(ts.size() == 0);
     }
 
@@ -667,14 +666,13 @@ TEST_CASE("capacity", "[capacity]")
 
         ts.reserve(10);
         ts.push_back({0, 1});
-        REQUIRE(ts.capacity() == 10);
+        REQUIRE(ts.capacity() >= 10);
         REQUIRE(ts.size() == 1);
 
         ts.shrink_to_fit();
         REQUIRE(ts.capacity() == 1);
         REQUIRE(ts.size() == 1);
     }
-#endif
 
     SECTION("clear")
     {