Once a Bot is created and turned ON, it keeps checking for new data (as per your Trigger event).
The frequency with which it checks for data is called date check interval. This interval varies depending on the Plan. Lower interval is better. Please check the pricing section for the same.
Whenever new data is found as per the trigger condition, the Bot will run and all the Actions are performed.
The monthly Action quota is consumed only when the Bots find new data and run the Actions. It is Not consumed when the Bot merely checks for new data but does not find any.
What if there is new data in between check interval?
All new data will be processed as and when the Bot checks for data. So the data that comes in is accumulated and processed in batches.
However, there are some rare exceptions where the Bot may not process ALL the new data. For example, when you do a bulk import of data into your CRM. In such cases, we typically process the latest 100 entries. Very few Apps and triggers have such exceptions.