diff --git a/datman/src/bin/datman.rs b/datman/src/bin/datman.rs
index 19f890f..b460501 100644
--- a/datman/src/bin/datman.rs
+++ b/datman/src/bin/datman.rs
@@ -114,6 +114,10 @@ pub enum DatmanCommand {
     Report {
         /// Name of the pile to report on.
         pile_name: String,
+
+        /// Don't summarise months.
+        #[clap(long)]
+        individual: bool,
     },
 
     #[clap(name = "_backup_source_responder")]
@@ -313,13 +317,17 @@ fn main() -> anyhow::Result<()> {
             backup_source_responder::handler_stdio()?;
         }
 
-        DatmanCommand::Report { pile_name } => {
+        DatmanCommand::Report {
+            pile_name,
+            individual,
+        } => {
             let descriptor = load_descriptor(Path::new(".")).unwrap();
             let destination = &descriptor.piles[&pile_name];
-            let report = datman::commands::report::generate_report(destination, &descriptor)?;
+            let report =
+                datman::commands::report::generate_report(destination, &descriptor, !individual)?;
 
-            datman::commands::report::print_report(&report)?;
             datman::commands::report::print_filesystem_space(&destination.path)?;
+            datman::commands::report::print_report(&report)?;
         }
     }
     Ok(())
diff --git a/datman/src/commands/report.rs b/datman/src/commands/report.rs
index 7c3b205..f9b92f6 100644
--- a/datman/src/commands/report.rs
+++ b/datman/src/commands/report.rs
@@ -29,6 +29,7 @@ use yama::pile::{DebugStatistics, Pile, RawPile};
 pub struct Report {
     pub last_source_backups: BTreeMap<String, Option<DateTime<Utc>>>,
 
+    pub chunk_usages_aggregated: bool,
     pub chunk_usage: BTreeMap<String, Sizes>,
 
     pub debug_stats: Option<DebugStatistics>,
@@ -64,6 +65,7 @@ fn condense_chunk_id(chunk_id: ChunkId) -> CondensedChunkId {
 pub fn generate_report(
     dest_pile_descriptor: &DestPileDescriptor,
     descriptor: &Descriptor,
+    aggregate_chunk_usage_by_month: bool,
 ) -> anyhow::Result<Report> {
     let pile_descriptor = load_pile_descriptor(&dest_pile_descriptor.path)?;
     let pile = open_pile(&dest_pile_descriptor.path, &pile_descriptor)?;
@@ -71,6 +73,7 @@ pub fn generate_report(
     let debug_stats = pile.raw_pile.debug_statistics()?;
 
     let mut pointers_to_parent_and_chunkids = BTreeMap::new();
+    let mut pointergroups_to_pointers: BTreeMap<String, Vec<String>> = BTreeMap::new();
 
     info!("Collecting chunk IDs... This will probably be slow.");
     for pointer_name in pile.list_pointers()? {
@@ -79,6 +82,20 @@ pub fn generate_report(
             .context("listed pointer doesn't exist")?;
         let root_node = retrieve_tree_node(&pile, pointer.chunk_ref)?;
         let pointer_chunk_ids = collect_chunk_ids(&pile, &root_node.node)?;
+
+        let pointergroup = if aggregate_chunk_usage_by_month {
+            let (base, date_time) =
+                split_pointer_name(&pointer_name).context("Can't split pointer name")?;
+            format!("{}+{}", base, date_time.format("%Y-%m"))
+        } else {
+            pointer_name.clone()
+        };
+
+        pointergroups_to_pointers
+            .entry(pointergroup)
+            .or_default()
+            .push(pointer_name.clone());
+
         pointers_to_parent_and_chunkids
             .insert(pointer_name, (pointer.parent_pointer, pointer_chunk_ids));
     }
@@ -87,12 +104,18 @@ pub fn generate_report(
     // At the same time, we can also calculate 'rollup' sizes.
     let mut chunk_sharer_counts: BTreeMap<CondensedChunkId, u16> = BTreeMap::new();
 
-    let mut pointer_stats: BTreeMap<String, Sizes> = BTreeMap::new();
+    let mut pointergroup_stats: BTreeMap<String, Sizes> = BTreeMap::new();
+
+    for (pointergroup_name, pointers_in_group) in pointergroups_to_pointers.iter().rev() {
+        let mut deduped_chunks = BTreeSet::new();
+
+        for pointer_name in pointers_in_group {
+            deduped_chunks.extend(iter_over_all_chunkids_incl_parents(
+                &pointers_to_parent_and_chunkids,
+                &pointer_name,
+            ))
+        }
 
-    for pointer_name in pointers_to_parent_and_chunkids.keys().rev() {
-        let deduped_chunks: BTreeSet<CondensedChunkId> =
-            iter_over_all_chunkids_incl_parents(&pointers_to_parent_and_chunkids, &pointer_name)
-                .collect();
         let mut rollup_count = 0;
         for chunk in deduped_chunks {
             let count = chunk_sharer_counts.entry(chunk).or_default();
@@ -101,15 +124,23 @@ pub fn generate_report(
                 rollup_count += 1;
             }
         }
-        let entry = pointer_stats.entry(pointer_name.to_owned()).or_default();
+        let entry = pointergroup_stats
+            .entry(pointergroup_name.to_owned())
+            .or_default();
         entry.rollup = rollup_count;
     }
 
     // Now go through again and update all the stats!
-    for pointer_name in pointers_to_parent_and_chunkids.keys().rev() {
-        let deduped_chunks: BTreeSet<CondensedChunkId> =
-            iter_over_all_chunkids_incl_parents(&pointers_to_parent_and_chunkids, &pointer_name)
-                .collect();
+    for (pointergroup_name, pointers_in_group) in &pointergroups_to_pointers {
+        let mut deduped_chunks = BTreeSet::new();
+
+        for pointer_name in pointers_in_group {
+            deduped_chunks.extend(iter_over_all_chunkids_incl_parents(
+                &pointers_to_parent_and_chunkids,
+                &pointer_name,
+            ))
+        }
+
         let mut unique_count = 0;
         let mut shared_count_by_sharers = [0u32; 256];
         let total_count = deduped_chunks.len();
@@ -128,7 +159,9 @@ pub fn generate_report(
             sharers_sum += (count as f64) / (sharers_minus_one + 1) as f64;
         }
 
-        let entry = pointer_stats.entry(pointer_name.to_owned()).or_default();
+        let entry = pointergroup_stats
+            .entry(pointergroup_name.to_owned())
+            .or_default();
         entry.moral = (sharers_sum.ceil() as u32) + unique_count;
         entry.unique = unique_count;
         entry.total = total_count as u32;
@@ -147,7 +180,8 @@ pub fn generate_report(
 
     Ok(Report {
         last_source_backups: last_backed_up,
-        chunk_usage: pointer_stats,
+        chunk_usage: pointergroup_stats,
+        chunk_usages_aggregated: aggregate_chunk_usage_by_month,
         debug_stats,
     })
 }