Note: This is generalities, and like the English language, programming has more than its fair share of exceptions.
In general, repeats of material for the PantheaCon schedule, especially in the 101 category are often accepted. If they get good feedback and great attendance we will accept repeats. Some items, like the longstanding Pomba ritual repeated for years but there were shifts in the ritual itself. In general an item can be accepted for a repeat for 3 years in a row then we ‘give it a break’ or ‘put it on vacation’ for a year or two then accept it again. Old favorites are great but we also need to keep the schedule fresh and if we rotate out a few of the favorites every year then there is a good mix of old stuff, new stuff and somewhere in between stuff.
A lot of times we do have presenters year after year but they change up what they are presenting. That counts as new stuff.
We know that coming up with new stuff can be hard. Freshening up material with the latest findings and thoughts is great. Make sure you reflect that in your description for the program book too. While I and the programming group are the first people to see your stuff we judge it by what the attendees are going to find interesting and if it looks like the same old stuff they may not come back.
…and I suspect this will raise as many questions as it answers.