How should licenses be managed?

#1
I found this sentence on the license list I bought.

In the future, please notice that we require a license deactivation before transferring it to a new, formatted or upgraded machine. Failing to deactivate a license will require a support pack purchase. Please make sure to backup installer files.

I don't think I can deactivate my license if my computer suddenly breaks down or something happens, can the backup installer file in that sentence solve that problem?
I want you to tell me how to do it.
Please reply.
Thank you.
cron