How often are monetized channels re-reviewed?

If you have a monetized channel, how long can you upload reused content before you are detected by the YouTube reviewers? I know they claim to check in periodically but I've seen many channels uploading nothing but copyrighted works for over a year and they are still able to run ads on their videos.

bots review the channels in 98% of cases thats why some get away with it by bypassing the detection. theres no way humans can review millions iof accounts periodically. they probably set it up so their bots run at certain times and if the bots find reused or similar contents, will automactically demonetise the channel/

i have the same doubt