[2013 998 RTL] I recently did the Smackdab 2017 Run, I filled my 998's oil to the Full line the night before our departure. Rode 500 miles to get to the start on Friday. (Did not check oil), got up after 4+ hours of sleep, Rode the Smackdab's 700ish miles from 6 AM to 8:45 PM Saturday. Went to Hotel. (Did not check oil). Sunday Morning, Rode home to MN, another 500+ miles, total was 1739miles. Checked oil, added 1/2 quart to get it back to the Full line (Doing a IBA SS1K on Wednesday). After reading here, I only fill it to the full line when I know I'm going to do a LONG mellow touring ride to get to a destination.
Day to day around town use, I keep it halfway between full and add on the stick.