I should look into the mechanics of duplexed incident metering -- the closest thing to that practiced by me would be measuring twice becuase I can be insecure about taking only one measure.
Like you, I'll measure once or twice in a shooting session. Last week I shot four hours and metered twice: once in bright light and again when the cloud rolled in. That was enough light information for the entire day. The EVs were 15 and 13... which may not have even been enough to make changing the shutter worthwhile.