Tags work for more general categories, I was thinking at a more granular level e.g.

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Time entries

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Ticket 123 - 0.5hrs

Stand up - 0.25hrs

Ticket 123 - 1.25hrs

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Total time

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Ticket 123 - 1.75hrs

Stand up - 0.25hrs

I guess you could achieve this with tags but you would potentially end up with lots of tags to manage!