diff --git a/bin/check_samplesheet.py b/bin/check_samplesheet.py
index 047b3fce..e9a7a178 100755
--- a/bin/check_samplesheet.py
+++ b/bin/check_samplesheet.py
@@ -115,7 +115,7 @@ def validate_unique_samples(self):
         Assert that the combination of sample name and FASTQ filename is unique.
 
         In addition to the validation, also rename all samples to have a suffix of _T{n}, where n is the
-        number of times the same sample exist, but with different FASTQ file(s).
+        number of times the same sample exist, but with different FASTQ files, e.g., multiple runs per experiment.
 
         """
         assert len(self._seen) == len(self.modified), "The pair of sample name and FASTQ must be unique."