Back when I was doing Dec, I’d do work on this a couple times a week.
Agree with earlier posts re: 1000m is about guts. Anybody who can run low 50’s 400m can go well into the 2:40s in the 1000. Probably faster.
1500 is about pace – we’re not running 4:00 (Except Joe Detmer) so it’s about knowing and keeping your pace more than being a great middle distance runner. When my 1500 was at its best (4:22), I’d do a 1500m warm-up prior to my track day as follows:
400m jog/400m race pace (70 seconds)/400m jog/300m race pace (50 seconds).
Didn’t thrash my legs for the rest of my workout, + got me used to the right pace.