1. A method, comprising: detecting a budget event for a circuit design; responsive to detecting the budget event, calculating, using a processor, a delta for a selected combinatorial circuit element of the circuit design using an incoming slack and an outgoing slack of the selected combinatorial circuit element; wherein calculating a delta comprises subtracting the outgoing slack of the selected combinatorial circuit element from the incoming slack of the selected combinatorial circuit element and dividing a result of the subtraction by two; and adjusting, using the processor, a delay budget for a connection of the selected combinatorial circuit element using the delta responsive to detecting the budget event.