diff --git a/composer.json b/composer.json
index 843032f..8ad8e51 100755
--- a/composer.json
+++ b/composer.json
@@ -29,6 +29,6 @@
   "scripts": {
     "cs": "./vendor/bin/php-cs-fixer fix --dry-run --diff --config codestyle.php",
     "csf": "./vendor/bin/php-cs-fixer fix --diff --config codestyle.php",
-    "test": "./vendor/bin/phpunit tests --colors always"
+    "test": "./vendor/bin/phpunit tests --colors=always"
   }
 }
diff --git a/readme.md b/readme.md
index 0064217..35d2504 100644
--- a/readme.md
+++ b/readme.md
@@ -8,21 +8,23 @@ What's a heatmap? It is a data visualization technique that shows magnitude of a
 ![./docs/github.png](./docs/github.png)
 
 ### Installation
-The Heatmap is distributed as Composer library via Packagist. To add it to your project, just run:
-```
+The Heatmap is distributed as Composer library via [Packagist](https://packagist.org/packages/blumilksoftware/heatmap). To add it to your project, execute the following command:
+
+```bash
 composer require blumilksoftware/heatmap
 ```
 
 ### Usage
 You can use any set of data you want. By default, dates will be taken from `"created_at"` key of arrays or objects implementing `\ArrayAccess` interface. Builder accepts also objects implementing `\Blumilk\HeatmapBuilder\Contracts\TimeGroupable` contract with mandatory `getTimeGroupableIndicator()` method returning a string with proper date:
+
 ```php
 $data = [
-    ["created_at" => "2022-11-01 00:00:00", /** (...) */],
-    ["created_at" => "2022-11-03 00:00:00", /** (...) */],
-    ["created_at" => "2022-11-16 00:00:00", /** (...) */],
-    ["created_at" => "2022-11-16 00:00:00", /** (...) */],
-    ["created_at" => "2022-11-18 00:00:00", /** (...) */],
-    ["created_at" => "2022-11-19 00:00:00", /** (...) */],
+    ["created_at" => "2025-11-01 00:00:00", /** (...) */],
+    ["created_at" => "2025-11-03 00:00:00", /** (...) */],
+    ["created_at" => "2025-11-16 00:00:00", /** (...) */],
+    ["created_at" => "2025-11-16 00:00:00", /** (...) */],
+    ["created_at" => "2025-11-18 00:00:00", /** (...) */],
+    ["created_at" => "2025-11-19 00:00:00", /** (...) */],
 ];
 ```
 
@@ -36,44 +38,68 @@ Method `build()` returns array of tiles that can be serialized into JSON with si
 ```json
 [
   {
-    "label": "2022-11-16",
+    "label": "2025-11-16",
     "count": 2,
     "description": ""
   },
   {
-    "label": "2022-11-17",
+    "label": "2025-11-17",
     "count": 0,
     "description": ""
   },
   {
-    "label": "2022-11-18",
+    "label": "2025-11-18",
     "count": 1,
     "description": ""
   },
   {
-    "label": "2022-11-19",
+    "label": "2025-11-19",
     "count": 1,
     "description": ""
   },
   {
-    "label": "2022-11-20",
+    "label": "2025-11-20",
     "count": 0,
     "description": ""
   },
   {
-    "label": "2022-11-21",
+    "label": "2025-11-21",
     "count": 0,
     "description": ""
   },
   {
-    "label": "2022-11-22",
+    "label": "2025-11-22",
     "count": 0,
     "description": ""
   },
   {
-    "label": "2022-11-23",
+    "label": "2025-11-23",
     "count": 0,
     "description": ""
   }
 ]
 ```
+### Customizing the Heatmap Builder watching period
+
+By default, the `HeatmapBuilder` automatically sets its observation period to the last seven days if no custom period (`$period`) is provided during instantiation. This default behavior ensures a rolling seven-day view from the current day.
+
+If you need to specify a custom period (e.g., the entire month of January), you can achieve this by explicitly passing a `CarbonPeriod` instance to the builder, as shown in the example below:
+
+```php
+// Define a custom period for the entire month of January 2025
+$period = CarbonPeriod::create(
+    Carbon::parse('2025-01-01'),
+    '1 day',
+    Carbon::parse('2025-01-31')
+);
+
+// Instantiate the HeatmapBuilder with the custom period
+$builder = new HeatmapBuilder(
+    now: Carbon::now(),
+    periodInterval: PeriodInterval::Daily,
+    period: $period // Include the custom period
+);
+
+// Generate the heatmap data
+$result = $builder->build($data);
+```
diff --git a/src/PeriodActions.php b/src/PeriodActions.php
index 59994ed..72d4086 100644
--- a/src/PeriodActions.php
+++ b/src/PeriodActions.php
@@ -8,49 +8,45 @@
 
 trait PeriodActions
 {
+    private const UNIT_HOURS = "hours";
+    private const UNIT_DAYS = "days";
+    private const UNIT_WEEKS = "weeks";
+    private const UNIT_MONTH = "month";
+    private const UNIT_YEAR = "year";
+    private const UNIT_DECADE = "decade";
+    private const DEFAULT_TIME_UNIT_DURATION = 1;
+
     public function forLastMonth(): static
     {
-        $start = $this->now->copy()->subMonth();
-        $end = $this->now->copy();
-
-        $this->period = new CarbonPeriod($start, $this->periodInterval->value, $end);
-
-        return $this;
+        return $this->setPeriodFromDuration(self::DEFAULT_TIME_UNIT_DURATION, self::UNIT_MONTH);
     }
 
     public function forLastYear(): static
     {
-        $start = $this->now->copy()->subYear();
-        $end = $this->now->copy();
-
-        $this->period = new CarbonPeriod($start, $this->periodInterval->value, $end);
-
-        return $this;
+        return $this->setPeriodFromDuration(self::DEFAULT_TIME_UNIT_DURATION, self::UNIT_YEAR);
     }
 
     public function forLastDecade(): static
     {
-        $start = $this->now->copy()->subDecade();
-        $end = $this->now->copy();
-
-        $this->period = new CarbonPeriod($start, $this->periodInterval->value, $end);
-
-        return $this;
+        return $this->setPeriodFromDuration(self::DEFAULT_TIME_UNIT_DURATION, self::UNIT_DECADE);
     }
 
     public function forNumberOfTiles(int $number): static
     {
-        $start = $this->now->copy()->sub(
-            $number,
-            match ($this->periodInterval) {
-                PeriodInterval::Hourly => "hours",
-                PeriodInterval::Daily => "days",
-                PeriodInterval::Weekly => "weeks",
-                PeriodInterval::Monthly => "months",
-            },
-        );
-        $end = $this->now->copy();
+        $unit = match ($this->periodInterval) {
+            PeriodInterval::Hourly => self::UNIT_HOURS,
+            PeriodInterval::Daily => self::UNIT_DAYS,
+            PeriodInterval::Weekly => self::UNIT_WEEKS,
+            PeriodInterval::Monthly => self::UNIT_MONTH,
+        };
+
+        return $this->setPeriodFromDuration($number, $unit);
+    }
 
+    protected function setPeriodFromDuration(int $duration, string $unit): static
+    {
+        $start = $this->now->copy()->sub($duration, $unit);
+        $end = $this->now->copy();
         $this->period = new CarbonPeriod($start, $this->periodInterval->value, $end);
 
         return $this;