Correct way to use chewies?

I use chewies several times a day, usually just by biting them a few times after popping my trays back in - to make sure they feel slotted into place properly. However I've seen people mention using them for 10/20 minutes a I supposed to sit and spend several minutes at a time biting them?? I'm on tray 7 and so far all seems to be going ok, but I don't want to find I'm causing any slow progress due to not using chewies properly!!

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