I used to dread having 100 emails sitting in my inbox that are months old that needed to be responded to. Calendy is a small service that changed my life in that it made it super easy to schedule short 20 minute phone calls with people to follow up on email threads that I just never found the energy to go back and forth on to schedule appointments.
Whenever I get an email chain that goes beyond 3 replies, I just shoot them a calendy link to have them schedule a 20 minute phone call. It takes zero work to do this and most of the time people won't even book a time to talk on the phone which is a relief and saved me the effort of wasting time on neverending email chains.