Fixed deadlines keep things simple
A fixed deadline gives every player one clear cutoff, usually before the Sunday early games. It is easy to explain and easy for commissioners to enforce.
The tradeoff is that Thursday, Friday, or Saturday games need special handling. If a team plays before the fixed deadline, that team should lock at kickoff.
Rolling locks give players more flexibility
Rolling locks let each matchup stay editable until its own kickoff. Players can wait on injury news and weather as long as their selected team has not started.
This format feels fair, but it requires software to track every game clock correctly. Manual spreadsheets often struggle with rolling locks.
Hybrid rules are often best
Many pools use a hybrid rule: each pick locks at the earlier of the team kickoff or the weekly fixed deadline. That prevents late swaps while still handling early-week games correctly.
Whatever rule you choose, write it down before invites go out so players know exactly when their picks become official.