Leads come in all hours of the day. Unless you have someone answering the phones 24/7, you should have Lead Valet turned ON. This will ensure that all of your leads, no matter what time they arrive, are followed up with as soon as possible. Any leads that arrive outside of business hours are parked in a queue and will begin calling your team as soon as business hours open the next day. You can create a custom routing schedule for after hour leads or follow normal routing rules you have set for your real time leads.
Make sure you have 'Lead Valet' selected as a lead type for one of your routing rules.