This is not Adobe. Rather user to user.....not sure what you mean by "How many times can I redeem the serial keys?"
The typical reply about serial numbers goes as follows....
Adobe allows you to use the same purchased activated serial number for Premiere Elements on no more than 2 of your computers. And the license goes on to say, not at the same time.
Photoshop Elements 13 and Premiere Elements 13 are standalone products, each coming with an Elements Organizer. When the two are on the same computer, they share the same Elements Organizer.
Please check out the following as its relates specifically to Student Teacher version.
What is written there more or less confirms what I have written above.
Please review and consider. Any questions or need clarification, please do not hesitate to ask.