I'm not sure what prompted me to count how many days I've hiked so far on long-distance trails. I did that recently by totaling the days I've hiked on the AT (179 days), the PCT (172 days), and the Benton MacKaye Trail (22 days). When I added to that the 130 days I've hiked so far on the CDT, the result was 503.
That number was a little startling to me, even though I was the person who did the hiking. It's more than a year of my life, and I'm not yet done with this trail.