Maybe just a matter of perspective of terminology.
My formula is 3 “non-negotiable” workouts per week. 2 interval sessions that are almost always done on the trainer, plus a long ride that is mostly endurance/tempo, but varies based on time of year and goals. The long ride might have a group ride sandwiched in the middle, so not as structured as the interval days, but there are still zone and tss/Kj goals. All 3 of those create a good bit of stress and I try to sandwich easy “filler” days in between them. That’s what I call them (right or wrong), but they have specific goals and are not junk miles or recovery rides. They are typically 1-2 hours of mid to high endurance works. I don’t think of them as work (almost always under 100 tss), it’s just a fun bike ride at a somewhat deliberate power target. The key is to be disciplined and not chase KOM’s, blast up hills, or do stupid stuff that might affect the quality of the 3 focused days. If I’m feeling significant fatigue on these easy days, I might turn them into a recovery day and just spin for an hour. I guess I just draw a line between 2 buckets of training - 3 key workouts is the “focused” bucket, the other bucket is as much Z2 “filler” as I can do without affecting the 3 key workouts. That doesn’t mean the filler stuff isn’t important, I think it’s the only way to push overall training stress high without going off the cliff.
