Say that for a month, each day you go back to the first of the month (January).
There are now 32 of you.
One year later, 366 of you.
You decide to make a real nuisance of yourself, and there are eventually thousands of you, from child up to the most recent age at which you "chronoported".
After all you could take the device back yes? Give it to your seven year old self to use?
Sounds like fun. Maybe Elvis has one.