# Tags - Best Practices

This topic covers best practices when using Tags within a project.

- When creating Tags, use a period character between names (e.g. "VisionPro.TaskPins.BlobCount") to categorize your tags. This allows the Tags Window to create a tree structure of your tags, and also assists with code completion.

- When naming tags, avoid using the terms "Devices", "FileSystem", "HMI", "Pages", "System" or "Tasks". Using these terms may cause a conflict with an internal tag or object, and may be difficult to locate because it will be interspersed with the existing internal tags.
- Minimize writing to a Persistent tag in Tasks, because it performs a disk I/O operation, so it may affect timing (and fluctuations in timing). Reading, however, has no impact on performance.
- When using a Persistent tag, only serializable Data Types should be used. Otherwise, startup errors will occur.

Note:

- There is no limit on the number of tags that can be created in a project.
- Runtime performance is not affected by the number of tags.
- Tags created in the Tag Manager are thread safe.