For years now, this is how I've order my contact lenses:

Every few months I get a text message from a website I once visited around 5 years ago. I purchased some lenses and never visited again. They know how many lenses I buy and how long they'll last. Then they send me a message…

I love this transaction for many reasons:

1. I don't need to install an app or sign in to a website
2. It works even if I change my phone
3. I can ignore it if I like
4. I can pull up a message from months ago and respond.
5. There is no payment confirmation required.

One 'YES' and they arrive the next day with a complimentary bag of Haribo.