The following picture shows a month’s worth of bandwidth usage on the Syndic8 server:
In one month, Syndic8 pulled in 139 GB of data and gave out 213 GB, for a total transfer of 353 GB. Fortunately, my hosting plan at Bocacom includes 500 GB of transfer per month.
The periodic spikes occur when the Syndic8 poller goes out and downloads the latest info from each feed. This happens twice a day for most feeds.