here is a little anecdote for you. In college I was on the team with the NAIA National CC champ. You would think that I and the other guys on the team would be following what he was doing, but we didn't. On his easy days he ran so slow almost no one ever ran with him. I wish I could tell what pace he was running but since I never ran with him, and never ask, I don't know. I'm not even sure how fast I was going as no one was ever timing these runs - so this is pure speculation. I would say I was going 7:00 pace (but it certainly could have been faster = possibly 6:30) and the national champ - could have be closer to 8:00. I never ran slow....as few years after college a few of us would get together for longs am runs and it seemed like we were going over 7:00 (and I absolutely hated it - it felt so slow and pointless...but guess what, I started getting faster on my tempos). The only thing I can attribute this to was going slow for the first time, and going longish - these were 14 mile runs. I rarely went over 10 before that. My times improved from 25:30 8k (both on the roads and in CC meets) to 23;45 in about 9 months not by running more miles (my mileage was actually going down) but from these longer slower runs.
That's a great story! I think longer, slower runs have their place. HR monitors (even somewhat inaccurate wrist monitors) give you a *rough* idea of effort. Even if you don't look at the paces/times on them, I'm noticing that just sticking to zones has helped me stay disciplined for EZ runs (i.e. I often don't really know my EZ pace until after the run is done, but I know to keep the HR--like a speedometer in a car--under 148-150-ish for all of the EZ run).
It allows one to go crush tempos and hard workouts. EZ runs are basically bridges between LRs and workouts.
Strava time may show up slow (9:10-9:55 on EZ days) but I'm all good.
But you generally don't want to "crush tempos and hard workouts".
Undertrained better then Overtrained (available and competing vs injured)
Depending on other days - generally a little sore going into you Long (recovery) day - with the goal recovery (as this poster said)
Go into your harder workout type days feeling great to max the prescribed effort on those - and be a bit sore so you need your recovery day to be...well a recovery day-
If you're doing workouts right, they'll pull your easy pace up. Your legs will just be moving faster during the easy run on their own and you won't need to push the pace.