Those are observations, not rules.
There is another “rule of thumb” that fields work with 10-15 mins playing. So the luck/wealth audios that are around or longer than 10 mins can be listened to just once.
The newer audios also need less listening, so maybe 5 mins is enough.
Nonetheless, you have to find out for yourself. I need from 30 mins to 45 to get effects.
Obviously there could be many reasons of why you don’t see results. Listening time shouldn’t be one but if you truly aren’t listening enough to move through resistance and gain momentum…it could be that.