Add a value to a value

Configuration
1

In Home Assistant, I need to store a value long term. There is a sensor that exists which keeps track of daily runtime for something. Just before the day ends, I want to take that value via automation and add it to another sensor or something so I can keep track of it.

What is the best approach here?

2

You can use Trigger-based Template sensors to do what you have described. Make sure to assign an appropriate state-class to have your values stored as long-term statistics.