When I was 25, it was 10-mile race pace. I did two sub-60 ten-milers in Central Park back then. Good solid long tempo pace.
At age 50, it was a tad slower than one-mile race pace. I would sometimes do workouts of 10 x 60 sec. @ 6 minute pace, with floats in between.
These days, at age 60, it's a pace I rarely touch. If I do 10 x 60 sec. @ 7:00, I'm doing very well.
But occasionally, kicking hard at the end of a 5K, I get there.