Thought this might be useful data for someone thinking about setting a sub-4 marathon goal. I really appreciated everyone who shared about their experience on this subreddit as I was planning for my own race.

Marathon time: 3:57:55
Course: Shanghai, flat course
Training block (ie. focused run plan): 12 weeks
Average mileage: 37 miles
Peak mileage: 54 miles
Longest run: 17 miles

Year long training: Preceding the training block, I did a gradual ramp up from no running to 15 mpw over the course of the year - my average weekly mileage this year has been ~9 mpw. I did run the year before (average 45 miles a month) but took a winter break after moving. In March I ran a 2:09 half marathon with very limited training (8 mpw for a month).

Previous PRs: 1:50 half marathon with a few significant hills (best longer distance running shape I've been in before) and a 48:30 for a flat 10k.

Background: 31F, college soccer, always generally fit but more a sprinter than long distance runner

Training: The Hanson plan but I only averaged 4-5 runs per week (though occasionally did all 6!) and really didn't follow it closely the last two weeks because I had an ill-timed, last minute work trip. The Hanson plan was good for suggested run pacing though! I noticed my cadence really increase with the higher mileage too.

Race day strategy and fueling: toast and an espresso shot before heading to the course. Casual start. tried to refrain from zigzagging around people at the beginning and wasting my energy. Could easily chat with other runners up until 15 miles in. Took water/Gatorade at almost every pitstop (every 3 miles or so). Had two banana halves and two gels. Could not get myself to eat anything in the last 8 miles. One bathroom pit stop at mile 18/ glad I carried TP in my vest. So happy I wore a hat and probably didn't need a vest but it was comforting to have phone, extra gels, tp. Listened to music starting mile 10. Headphones died at mile 22. I don't think really affected me. Max temp was 73° for the day- a little to warm for my liking.

Self assessment: my goal was a sub 4 hr so I am happy with the result. I really slowed down the last three miles (just a grind, no particular cramping) so I think I could have paced the beginning better or just build up more strength but it was a learning experience. The goal always felt realistic during training (Garmin wildly thought I could run a 3:30 and Strava predicted 4:01 - then after I ran my marathon, now predicts 3:51). I stressed a little about missing or modifying quite a few of the workouts in the last two weeks but it turned out to be fine. In training, I really enjoyed group runs and didn't stress about pacing except for the tempo run and the speed/strength workouts. After this race, I think half marathons or 10ks are the distance for me. Marathon running felt harder to make work with my lifestyle but I'm happy to have tried it! 

First marathon - Shanghai (sub 4 goal)