There is so much fun and learning to be had with cards.
When I first started with magic, they never left my side.

Nowadays, I do not carry cards at all, impromptu.
Having mastered the sleights, it is to easy to perform miracles using other peoples cards when the opportunity presents itself in social gatherings.
As a performer, I do not carry cards table-hopping. However, the question "do I carry cards?". Yes, X-Act by Mark Mason and Premonition by Eddie Joseph if I am table performing.

As I've gotten more into cards with a monster commute (about 90 minutes via bus and train) I usually have a deck of cards with me in my back pack. I'll practice double lifts, top changes, and various cuts while waiting for train or bus (weather permitting).

I don't have a guard, and my cards get beat up; I go through about a deck a month (not as bad as Richard Turner who's said to have had a 3-4 pack a day habit). I've started buying bricks of cards at Costco.