How critical is the Lead Response Time?
Lead quality degrades over time. If you don't respond to your leads, they grow cold and lose interest, either because they'd have moved on to other companies or their other responsibilities. So, in fact, the sooner you can respond to your leads, the better.
Why is this? Well, the internet has changed buyer behavior. Customers are doing significant online research about the products and services they're interested in, all without ever talking to another person. So when potential buyers do reach out, it's usually when they're very close to the purchase stage of their buyer's journey. And that's the best time to reach them—when they're interested in and ready to talk to a salesperson.
When you respond to your leads, the way of response and the frequency of response matters too. Are you reaching out via email or phone? You should probably be doing both. And you shouldn't give up after one attempt. Doing this helps you establish a relationship with your lead by nurturing them into prospects and customers.