Techniques for estimating the performance of a network device. In one set of embodiments, a network device can determine one or more performance metrics associated with a feature of the network device that is customizable by a user. An example of such a feature is a user-defined script that is executed via a scripting engine of the network device. The network device can then generate a performance estimate based on the one or more performance metrics. The performance estimate can indicate the likely performance of the network device with the feature enabled.