How do you keep track of Vouchers and its expiry?

Can put it all into your notes in your phone. Pin the notes so that it is always at the top :)

That makes it easy to use as well and you can even enter the expiry date if required.

Then yes, google calendar the expiry 1 week before it expires so you got time to chiong use finish.

Save them to tour

Use google calender to write down any dates you need to remember. Use google sheets to compile them in one place. Try and see what works for you.

I list them all down with the expiry on google keep so i have it handy.