A routine that only works on easy days isn't really a routine — it's a plan that falls apart the first time life gets busy. Building one that survives busy weeks matters more than designing an ideal routine for a perfect day.
Decide the smallest possible daily session you'd still consider "showing up" — often a single short lesson — and treat that as the actual daily commitment, not a fallback for bad days. On good days you'll naturally do more; on bad days, the floor is still low enough to clear, which is what actually keeps a streak (and the habit) alive.
"Habit stacking" — attaching a new habit to an existing, reliable one (right after coffee, right after your commute, right before bed) — removes the need to remember or decide when to study. The existing habit becomes the trigger, so the new one doesn't depend on willpower or memory each day.
A routine scheduled for a specific, consistent time of day is more resilient than one you intend to fit in "sometime today" — vague timing quietly loses to whatever else is competing for your attention, since it never has a specific moment to defend.
Decide in advance what a "minimum viable" bad-day session looks like (one lesson, five minutes, no exceptions) so you're not negotiating with yourself in the moment — see How to Stay Consistent for more on recovering after a missed day without spiraling into quitting entirely.
See also the reference page: How to Stay Consistent.
Designing the routine around an ideal day rather than a realistic bad day — a routine that only survives on easy days isn't resilient enough to become a lasting habit.
Attaching a new habit to an existing, reliable one (like studying right after your morning coffee) — the existing habit acts as an automatic trigger, so the new one doesn't depend on remembering or deciding each day.
A fixed, consistent time tends to be more resilient — vague plans to fit study in "sometime today" often lose out to whatever else is competing for attention that day.
Fall back to your predetermined minimum session (even a single short lesson) rather than skipping entirely — showing up in a small way keeps the habit and streak intact.