Coming into 2012 I had run 1:59 800, 4:34 1600, 9:43 3200 and 15:54 high school times. I got cut from my University team in 2012 and trained by myself since then. I started working with a coach in 2016 who has run 63:XX and 2:14:XX. Mileage has helped, but not being hurt since 2011 has helped more. Parentheses are the avg weekly mileage for the year.
2012 (45) - 15:30 5k, 26:02 8k, 32:12 10k
2013 (67) - 4:26 road mile, 15:04 5k, 25:48 8k, 31:51 10k
2014 (92) - 4:23 indoor mile, 8:45 3k, 14:57 5k, 25:30 8k, 31:24 10k, 69:06 HM
2015 (102) - 8:33 3k, 25:02 8k, 2:31:58 marathon
2016 (112) - 14:31 5k, 24:46 5mi, 30:47 10k, 67:32 HM
2017 (120 so far) - 14:27 5k, 24:12 5mi, 30:10 10k, 67:28 HM, 2:18:17 Marathon