diff --git a/zfs-backup.py b/zfs-backup.py
index 97efb06..84057ef 100755
--- a/zfs-backup.py
+++ b/zfs-backup.py
@@ -9,7 +9,7 @@ from pathlib import Path
 from re import search
 from subprocess import PIPE, Popen, call, check_output
 from sys import exit
-from typing import Optional
+from typing import Optional  # TODO replace with pipe notation
 from uuid import UUID
 
 import config
@@ -42,6 +42,10 @@ def main():
     manager.backup()
 
 
+# TODO tests
+# TODO docstrings
+# TODO first backup
+
 class Manager:
     def __init__(self, local_pool: Pool, external_pool: ExternalPool):
         self._local_pool = local_pool
@@ -92,6 +96,7 @@ class Manager:
         ]
 
     @staticmethod
+    # TODO make function
     def _get_regex_matching_backup_tags():
         return "@" + ".*".join([config.snapshot_tag, config.snapshot_interval])
 
@@ -230,6 +235,8 @@ class ZFS:
 
     @staticmethod
     def destroy(full_name, *, recursive=False):
+        # TODO condition must be "begins with"
+        #   or better argument should be a ZFSPath
         if config.local_pool_to_backup in full_name:
             raise Exception(DELETE_IN_LOCAL_POOL)
         cmdline = [config.ZFS, "destroy"]
@@ -260,8 +267,10 @@ class ZFS:
 
     @staticmethod
     def scrub(pool: str, *, wait_for_finish=True) -> None:
+        # TODO: check if scrub already in progress
         run_command([config.ZPOOL, "scrub", pool])
         if wait_for_finish:
+            # TODO make Ctrl-c interrupt this
             run_command([config.ZPOOL, "wait", "-t", "scrub", pool])
 
 
@@ -285,6 +294,7 @@ class Disk:
         for item in MAPPER_PATH.iterdir():
             if self._mapper_entry == item.name:
                 print(MAPPER_ENTRY_ALREADY_EXISTS, self._mapper_entry)
+                # TODO exit code constants
                 exit(1)
 
     @property
@@ -298,6 +308,7 @@ class Disk:
     def encrypt(self):
         if not self._decrypted:
             raise ValueError(NOT_DECRYPTED, self._name)
+        # TODO use run instead?
         get_output_of_command([config.CRYPTSETUP, "close", self._name])
         self._decrypted = False
 
@@ -330,14 +341,14 @@ class ExternalPool(Pool):
         if self._imported:
             raise ValueError(ALREADY_IMPORTED, self.name)
         self._disk.decrypt()
-        self._import_from_directory(MAPPER_PATH)
+        self._import_from_directory(MAPPER_PATH)  # TODO inline?
         self._imported = True
 
     def export(self) -> None:
         if not self._imported:
             raise ValueError(NOT_IMPORTED, self.name)
         self._export_pool()
-        self._disk.encrypt()
+        self._disk.encrypt()  # TODO inline?
         self._imported = False
         print(f"Exported {self.name}. Disk {self._disk.uuid} can be removed.")
 
@@ -345,6 +356,7 @@ class ExternalPool(Pool):
         ZFS.import_pool_from_directory(self._name, directory)
 
     def _export_pool(self) -> None:
+        # TODO cancel scrub if necessary
         ZFS.export_pool(self._name)
 
     def scrub(self) -> None:
@@ -371,6 +383,7 @@ class ExternalPool(Pool):
     # return [d for d in self.datasets if d.qualified_name not in do_not_backup_correct_name]
 
     def clean_old_snapshots(self):
+        print("Cleaning old snapshots")
         for dataset in self.datasets:
             dataset.clean_old_snapshots()
 
@@ -410,10 +423,12 @@ class Dataset:
             self._clean_old_snapshots_for_interval(interval, number)
 
     def _clean_old_snapshots_for_interval(self, interval: str, max_count: int):
+        # TODO this is somewhat similar to the regex method in Manager
         regex = ".*".join(["", config.snapshot_tag, interval, ""])
         snapshots = [
             snapshot for snapshot in self.snapshots if snapshot.matches_regex(regex)
         ]
+        # TODO function _get_n_oldest_snapshots
         if len(snapshots) > max_count:
             snapshots.sort()
             for snap in snapshots[:-max_count]:
@@ -453,6 +468,7 @@ class Snapshot:
         return Dataset(self._path.dataset)
 
 
+# TODO class CommandRunner
 def run_command(cmdline: list[str]):
     call(cmdline)