Long runs are all about the time and distance. I recall asking Donavan Brazier, the 2019 World Champion for 800 meters about his long runs, and he noted that, at the time (2020), he had a longest run of 8.5 miles.
In high school, our long runs were perhaps 12-14 miles. During college, I moved out to 16-18 miles, and as a junior and senior in college, did 18 miles, 20 miles then 22 miles and would repeat the cycle.
Most long runs were steady-state, but others had some race simulations and other fun things. I recall running one 22 miler in 90-100 degrees up in the Santa Cruz mountains and finishing with two long hill repeats. My coach wanted me to see how water could help. I had been drinking 10 ounces of water each couple of miles and by 12 miles, it was making a huge difference. At the end of 22 miles, I did two hill repeats and felt amazing. The next day, I was not in any distress and knew that water was the way to keep one together, especially in the heat.
NB 320. I began using this shoe in 1976, and as I began to do longer and longer miles. I also races in it. I recall the 1976 Christmas Relays, Santa Cruz to Half Moon Bay, where I ran a 10.5 mile leg. photo courtesy of Running Shoe Guru
2022 RunBlogRun Spring Middle Distance Daily Track Training (800m-5000m), Week 12, Day 7
Monday: warm-up, 40-50 minutes moderate running, 6 x 100m stride outs, cooldown
Tuesday: Warm-up, 12 x 300 meters hard, 200-meter jog, the pace is 1500m, 30-minute run, cooldown,
Wednesday: warm-up, 40-50 minutes, moderate running, 6 x 100m stride outs, cooldown
Thursday: Warm-up, 20 x 200m, at 3000m pace, 200m jog in between, cooldown
Friday: warm-up, 40-50 minutes moderate running, 6 x100m stride outs, cooldown
Saturday: warm-up, 800m, 1,500m, 3000m, or 5000m, cool down
Sunday: 70-75 minutes moderate pace, on trails