As far in advance as possible is always best for both live on-line and in-person events. The farther in advance that you reach out, the more likely I will be available. That said, on-line events are simple to set up and require no travel arrangements, so if I have an opening in my schedule we can usually make short-notice bookings work. Reach out at least 60 days in advance for in-person events. I only do a handful of them a year.