One of the concepts I find people misunderstand frequently is the recovery interval, either for the server as a whole or the per-database setting that was introduced in SQL Server 2012 for indirect checkpoints.
There are two misconceptions here:
The recovery interval equals how often a checkpoint will occur
SQL Server guarantees the recovery interval (i.e. crash recovery for the database will only take the amount of time specified in the recovery interval)
It’s good to keep this in mind.