The default is 3 min. The best practice is 1 min. This will allow Aisa to respond to your lead within 1 min of getting the leads information.
It is not typically recommended that the lead delay be extended to allow agents/ISAs to call the lead first. The reason being is that oftentimes agents/ISAs are not consistently calling the lead within 5 min 100% of the time thus leaving the lead unresponded to until Aisa kicks in after an extended amount of time. This leads to a lot of lost opportunity.