Thunderbird/Lightning offers 5 different time intervals for refreshing remote calendars, between "Every Minute" and "Every 60 Minutes".
But, my work requires me to have over a dozen remote calendars, most of which won't change more often than once or twice a week. The result is that even on the longest refresh interval Thunderbird spend a lot of time re-downloading and updating calendar data that doesn't need to be updates, and slows to a crawl while it is doing so.
Is it possible to tweak/adjust Lightning to have longer refresh times than allowed by default (e.g. once per day)?