I don't carry a cellphone. The rates are atrocious in Canada, and I don't like being rung when I'm out and about.

The biggest problem is 2-factor. Many services are starting to require it, which has led me to losing access to various accounts. Looking at you, Paypal.

Otherwise, it's fine. I make a paper shopping list. I schedule meetings in advance, and show up at the expected time. Uber isn't even in my city so there's no loss there.