Choose up to five games, set your rest days, print the calendar and tick it off.
Streaks fail for a boring reason: no rest days. A plan with seven training days breaks the first time life gets in the way, and once broken most people stop entirely. This builds a calendar with rest built in, rotating your chosen games so you never do the same thing twice running.
A seven-day plan has no slack. The first missed day is a failure, and a broken streak is where most people quit — not because they stopped wanting to, but because the plan had no way to absorb a bad day.
Five or six training days gives you the spacing benefit with somewhere for real life to go. It is not a weaker plan; it is the one you will still be running in a month.
Playing only the game you are already good at is the commonest way people plateau. Rotating a small set means you meet the same abilities in different formats, which keeps improvement going for longer.
Five games is about the practical limit. Beyond that you get too few repetitions of each to see any of them move.
A paper calendar on a wall is a better streak mechanism than an app notification, because it is visible without you choosing to look at it and there is nothing to dismiss.
The print button produces the calendar with tick boxes. Nothing here needs an account and nothing chases you — if you stop, you stop, and nothing is taken away.
Five or six. Spacing matters more than total time, and a rest day or two is what keeps the streak alive through a bad week.
Five to fifteen minutes. Accuracy on memory and attention tasks falls off sharply after about twenty minutes, so longer sessions mostly practise being tired.
Nothing. No XP is lost, nothing is locked and nothing will chase you. Start the next day — the plan has rest days precisely so this matters less.
Yes, and every game it schedules is free too. No account, no email, no download.
Beyond five you get too few repetitions of each one to see any of them improve. A small rotating set beats a large sampled one.