What is the Average Retention Rate After Invisalign if Retainers Are Not Used? (photo)

I've been doing some research on invisalign. I met with a provider and he stated my case would take 3-4 months to correct with invisalign. Will teeth fully revert back to their original positions post-invisalign without retention? Also, since my case is not severe, would it be possible to only wear my aligners less than the 24hr recommended time? Just curious as I may not be able to wear then during the day due to work. Thank you in advance.