ERPNext Notification for reached hours in a sales order

Hello,

i’m trying to set up notifications to alert us when we almost used up the billable hours of a sales order.

At the moment we have to manually check all projects where we gave a certain ammount of working hours to a customer and as soon as they are used up we send out a new quotation. This is very error-prone.

For example the customer ordered 100 hours and i want a notification when 80 hours are written in the project, so we know when to send out a new quotation and not use more hours, then the customer ordered.

Thank you!