- A few blank checks. Keep them in your billfold. And then when you remember rent is due or you encounter a scout selling their last box of your favorite cookie you can just say, "One moment please...while I totally handle this shit."
- Postage stamps. Like blank checks, they fit right in your billfold, so you can send that forgotten rent check as soon as you take an envelope from the office supply room. Bonus: the next time someone asks if you happen to have a stamp, you can be all, "WHY YES I DO." And as you whip that sheet of Forever stamps out of your wallet like some sort of preparedness magician, watch their eyes light up as they think, "Damn! This good Samaritan totally has a handle on shit!"
- A spare car key. If you don't have a AAA membership* but you do drive a car, the day will come that you lock your keys in it. And even if you do have a AAA membership, maybe you just don't feel like waiting 45 minutes for someone to come and unlock it in three seconds. So keep a spare car key in one of your credit card slots. And then when your car door slams shut just as you realize your keys are in the cupholder, instead of yelling something unsavory to the other motorists around you, you can be all, "Let me just get my spare key out of my wallet, because I'm clever and keep one there and what? Oh, this? This is just me totally handling this shit."
*Why don't you have a AAA membership? It costs like 1/4 of what a tow costs, and a membership covers four roadside assists per year! So go join online now, okay?