diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d239493..6f414bf 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -49,6 +49,6 @@ jobs:
         with:
           depwarn: error
       - uses: julia-actions/julia-processcoverage@v1
-      - uses: codecov/codecov-action@v3
+      - uses: codecov/codecov-action@v4
         with:
           file: lcov.info
\ No newline at end of file
diff --git a/.github/workflows/documentation.yml b/.github/workflows/documentation.yml
index 76aff3f..31c3146 100644
--- a/.github/workflows/documentation.yml
+++ b/.github/workflows/documentation.yml
@@ -9,7 +9,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - uses: julia-actions/setup-julia@latest
         with:
           version: '1'
diff --git a/.github/workflows/format_check.yml b/.github/workflows/format_check.yml
index 50bc51a..3e0d84f 100644
--- a/.github/workflows/format_check.yml
+++ b/.github/workflows/format_check.yml
@@ -13,13 +13,13 @@ jobs:
       - uses: julia-actions/setup-julia@latest
         with:
           version: '1'
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v4
       - name: Format check
         shell: julia --color=yes {0}
         run: |
           using Pkg
           # If you update the version, also update the style guide docs.
-          Pkg.add(PackageSpec(name="JuliaFormatter", version="1"))
+          Pkg.add(PackageSpec(name="JuliaFormatter", version="2"))
           using JuliaFormatter
           format("src", verbose=true)
           format("test", verbose=true)
diff --git a/src/calendar.jl b/src/calendar.jl
index c142148..14cf5c3 100644
--- a/src/calendar.jl
+++ b/src/calendar.jl
@@ -21,6 +21,16 @@ struct CalendarTimes{T<:Union{Dates.DateTime,TimeZones.ZonedDateTime}} <:
     start_date::T
     length::Int
     period::Dates.Period
+    total_duration::Float64
+    function CalendarTimes(
+        start_date::T,
+        length::Integer,
+        period::Dates.Period,
+    ) where {T<:Union{Dates.DateTime,TimeZones.ZonedDateTime}}
+        end_date = start_date + length * period
+        total_duration = Dates.value(Dates.Hour(end_date - start_date))
+        return new{T}(start_date, length, period, total_duration)
+    end
 end
 
 function CalendarTimes(
@@ -61,7 +71,7 @@ function CalendarTimes(
     return CalendarTimes(first, length, period)
 end
 
-_total_duration(ts::CalendarTimes) = sum(duration(t) for t in ts)
+_total_duration(ts::CalendarTimes) = ts.total_duration
 
 # Add basic functions of iterators
 Base.length(ts::CalendarTimes) = ts.length
diff --git a/src/op_scenarios/core_types.jl b/src/op_scenarios/core_types.jl
index 64f7573..be81f37 100644
--- a/src/op_scenarios/core_types.jl
+++ b/src/op_scenarios/core_types.jl
@@ -36,6 +36,7 @@ struct OperationalScenarios{T,OP<:TimeStructure{T}} <: TimeStructure{T}
     len::Int
     scenarios::Vector{OP}
     probability::Vector{Float64}
+    total_duration::T
     function OperationalScenarios(
         len::Integer,
         scenarios::Vector{OP},
@@ -59,7 +60,12 @@ struct OperationalScenarios{T,OP<:TimeStructure{T}} <: TimeStructure{T}
                 "This can lead to unexpected behavior."
             )
         end
-        return new{T,OP}(len, scenarios, convert(Vector{Float64}, probability))
+        return new{T,OP}(
+            len,
+            scenarios,
+            convert(Vector{Float64}, probability),
+            maximum(_total_duration(osc) for osc in scenarios),
+        )
     end
 end
 function OperationalScenarios(len::Integer, oper::TimeStructure{T}) where {T}
@@ -73,7 +79,7 @@ function OperationalScenarios(oper::Vector{<:TimeStructure{T}}) where {T}
 end
 
 function _total_duration(oscs::OperationalScenarios)
-    return maximum(_total_duration(osc) for osc in oscs.scenarios)
+    return oscs.total_duration
 end
 
 function _multiple_adj(oscs::OperationalScenarios, scen)
diff --git a/src/simple.jl b/src/simple.jl
index 9db9b98..90088c9 100644
--- a/src/simple.jl
+++ b/src/simple.jl
@@ -19,6 +19,7 @@ varying = SimpleTimes([2, 2, 2, 4, 10]) # 5 periods of varying length
 struct SimpleTimes{T} <: TimeStructure{T}
     len::Int
     duration::Vector{T}
+    total_duration::T
     function SimpleTimes(len::Integer, duration::Vector{T}) where {T<:Duration}
         if len > length(duration)
             throw(
@@ -27,7 +28,7 @@ struct SimpleTimes{T} <: TimeStructure{T}
                 ),
             )
         else
-            new{T}(len, duration)
+            new{T}(len, duration, sum(duration))
         end
     end
 end
@@ -36,7 +37,7 @@ function SimpleTimes(len::Integer, duration::Duration)
 end
 SimpleTimes(dur::Vector{T}) where {T<:Duration} = SimpleTimes(length(dur), dur)
 
-_total_duration(st::SimpleTimes) = sum(st.duration)
+_total_duration(st::SimpleTimes) = st.total_duration
 
 # Add basic functions of iterators
 Base.length(st::SimpleTimes) = st.len
diff --git a/src/strat_scenarios/strat_scenarios.jl b/src/strat_scenarios/strat_scenarios.jl
index a298424..4d36b2f 100644
--- a/src/strat_scenarios/strat_scenarios.jl
+++ b/src/strat_scenarios/strat_scenarios.jl
@@ -115,9 +115,11 @@ When the `TimeStructure` is a [`StrategicScenario`](@ref), `strat_periods` retur
 
 These are equivalent to a [`StrategicPeriod`](@ref) of a [`TwoLevel`](@ref) time structure.
 """
-strat_periods(ts::StrategicScenario) = StratTreeNodes(
-    TwoLevelTree(length(ts), first(ts), [n for n in ts.nodes], ts.op_per_strat),
-)
+function strat_periods(ts::StrategicScenario)
+    return StratTreeNodes(
+        TwoLevelTree(length(ts), first(ts), [n for n in ts.nodes], ts.op_per_strat),
+    )
+end
 
 """
     struct StratScens{S,T,OP<:AbstractTreeNode{S,T}} <: AbstractStratScens{T}