Checking only 1 sample per backup when there are thousands of files doesn’t make much of a dent, especially if only backing up once per day.
While backup-test-samples provides the option to test more, a user often will have no idea how many files they have in their backup.
From a user point of view, I would think the ability to specify what percentage of your backup you want checked after each backup would be a friendlier method than having to specify an absolute number of samples.
On a similar topic, should the default check be something like 1% of the backup set?
Assuming that duplicati keeps track of who’s already been checked (I believe I’ve read that it does), a rolling 1% would - assuming there isn’t too much change each day - in a reasonable amount of time have checked 100% of the backup.