The problem with a resolution is its shape
“Get fit this year” has a start date and nothing else. No rules, so nothing to comply with. No floor, so a bad day is undefined and therefore fatal. No finish, so there is no day on which you succeed and no window in which the rules are non-negotiable. It is an aspiration wearing a deadline's clothes.
A challenge supplies all three parts. That is the entire upgrade — not more ambition, more structure. The evidence on why January feels powerful and then stops working is on the arc versus resolutions page; this page is the menu.
Six worth running in January
| Challenge | Length | Pick it if |
|---|---|---|
| 75 Soft | 75 days | You want fixed rules without a restart clause. Finishes mid-March, as the weather turns — the best default. |
| 75 Hard | 75 days | You want absolutism, you already train most days, and January is genuinely clear. |
| 75 Medium | 75 days | You train already but the quarter has landmines. Scoring instead of restarting. |
| Operation 66 | 66 days | You want a routine designed to outlive its own finish line. |
| A 30-day reset | 30 days | You have never held a challenge and want to find out whether the format works on you. |
| One habit, 30 days | 30 days | You know exactly which single thing would change your year. The most underrated option here. |
Reading that table, most people should pick row one or row five. The instinct in the first week of January is to pick the hardest one available, and it is the same instinct that fills gyms until the second week and empties them after.
Start on the 6th, not the 1st
The counterintuitive one. A landmark start borrows real motivation — that is well evidenced — but it is borrowed at a poor rate: the boost is spent in about ten days, which is roughly when Strava's activity data shows the new-year cohort tapering. A start on the first also means day one lands on a hungover public holiday, and day two on the last day of a family visit — the two worst days of your quarter to be calibrating rules.
Starting on the first ordinary Tuesday of January costs you five days and buys you a normal week to write and test rules in. It also separates your attempt from a crowd that is visibly quitting around you, which matters more than it sounds in a month when everyone is posting about it.
Whatever you pick, do this before day one: write the outcome in one concrete sentence, define what “done” means for each rule and its bad-day floor, decide the missed-day policy in advance, and freeze the list after week one. Four steps, twenty minutes — the full procedure is on the rules page and works in any season.
Plan for the second week now
Assume motivation leaves around day 10 to 14, because for most people it does. That is not new information arriving — it is the schedule. Put a review date on day 12 and decide today what happens on it: hold the floors, not the ideal version, and change nothing else. An attempt that expects the dip survives it; an attempt that interprets the dip as evidence it picked the wrong goal does not.
If January goes wrong
Two honest weeks tell you which rule was written badly, which is information you cannot get any other way. Rewrite that one rule, restart the following Monday, and treat January as calibration rather than as a verdict on your year. The people who end up finishing something in March are rarely the ones whose January was clean — they are the ones who were still adjusting in February. That is also the argument for a less absolute challenge if your first attempt died on a single impossible rule, and for starting in December next year, so the landmark finds you already moving.