Which of these equivalent times are easier/harder in your experience?

I should add that I am over 40 now, picked up running as an adult (late 20s) and hit the 1:20 half / 2:56 full in my mid 30s. Have not raced in 4 years since the 1:20 half. I am probably in 1:28+ half "shape" now. Ridiculous, hence thought of looking at shorter/intermediate term goals to hit.

the 1000 and mile are easiest

Then the 5000/10000

3000 in sub-10:00 is next

Then the 1/2

Hardest is the marathon

thank you I think most younger people would agree with that, while for old folks like me it's the reverse order. When I ran 1:20 half, I would do 200s in 37-39 and even 36 would be insanely fast...

But now that I am both old AND restarting, perhaps I do it in order and start with the shorter stuff for fun. I have a decent base now of slow running.

In my experience sub 2:50 marathon (which I have NOT done) takes a long time of dedication and consistency, while the 1000 in 3' has a lot of innate talent. The 10k and half are decent middle grounds.

In my opinion,

2:50 (6:29/mi) > 1:20 (6:05 pace) > 36:00 (5:48/mi) = 5:00 > 10:00 (5:23/mi) > 17:30 (5:38/mi) > 3:00 (4:50/mi)

It depends on your strengths as a runner of course. I could do comfortably any of these on any given day as a young 15 min 5000m runner, except for the 2:50 marathon and 1:20 half which would actually require proper preparation. Anyone capable of a sub 5 mile should also have sub 3 1k ability.

Yeah I think the 5 min mile is much harder than the 3 min 1000, but again I've never been even close to any of that. My fastest mile and 1000 are 5:27 and 3:19 respectively, both en-route to a 23ish (5:47 or so) 4-miler. Would require significant training to learn to run that fast!

3 min 1000 is 36 seconds per 200. Perhaps best way to get started is to start doing 200 intervals, get them down towards that 36, and then shortening rests.

10 min 3000 is 1:20 per 400 (40 sec per 200). That seems to be a reasonable starting point, too?

You asked which marks are easier but then changed your criteria to which ones you are more likely to hit. The 1st question applies to all runners. It goes easiest to hardest. We don't know the answer to the 2nd question. Only you do.

I believe most runners would achieve these marks in order, as they age (except most people never run a competitive 1000, and Americans run a 3200).

Kids develop the speed and enough staying power to hit the shorter distance marks first and then move up over time as their endurance develops. Then a lot of good older runners can still run the longer races but lose the turn over speed to run a 5:00 mile.

thanks for keeping me honest (no sarcasm). I think that's fair to say they equivalent times are in order from easiest to hardest, with no outlier.

gives a nice "to-do" list to progress towards for many casual runners like me

can someone (over 40) who's run a sub-3 marathon before "restart" or re-learn speed and go in ascending order like a kid, or would it make more sense to "descend"?

maybe skip the marathon as it's so specific, but maybe train for half, then 10k, then 5k, then 3000 etc.

Probably not. Even for older folks might need to relearn in ascending order.

From Experience:

The marathon is the hardest on that list. Next up would be either the 3k or half marathon. The 1000 is the easiest. I’ve broken all of these barriers. I was sub 3 in the 1k before I was sub 5 in the mile. A 10 minute 3k is like a 10:40 2 mile, I was a 4:46 miler when I was running around that. The Marathon is the hardest on this list due to mental toughness and the training that it takes. I ran 4:10 in the mile in college and shortly after ran a marathon in the low 2:40s and it was significantly harder than I thought it would be. The VDOT calculators will tell you that 4:59 or 5 flat is equal to a 2:5X marathon but you have to do a ton of running 80 plus miles a week to run 2:5X with only 5 minute mile speed. The marathon takes mileage, you can’t natural talent your way through it. When I was a 4:30 miler and 16:00 5k guy I had the speed to run in the 2:30s in the marathon but there was no way I was even breaking 3 if I attempted one. People don’t realize how hard the marathon can actually be if not properly prepared.

I'll talk about myself there.

I'm in my late 30s, i recently raced a 1k track in 3'02 (my first ever, only ran 5k-10k-HM-M). With no specific training, no 200m, no 400m, but a decent 5k shape 16'50 three weeks before. With specific training and a competitive race, 2'55 1k should be possible.

For me, 2:50>1:20>3:00>10:00>36:00>17:30

I understand what you're saying but i disagree.

Good track times requires talent. And you can't buy talent.

Whereas you can become a decent marathonian just by training well and do mileage.

Look at all these sub-3h marathoners very barely breaking the sub-40' in 10k, which is a joke.