Always keep plenty of business cards on hand. I keep some in my wallet. Tons of them in my car, in the glove box, etc.,.
Don’t be afraid to keep multiple versions. I always encourage people to maintain a couple different sets of cards. Perhaps one set has your address on it, where the other one doesn’t. Or perhaps one is glossy to match your branding, but you maintain an alternate non-gloss version that can be written on in pen. Whatever the case, more than one version of your business cards can be wise.