15. A 24-hour roadside assistance number on speed dial
It doesn't matter if it's AAA, your insurance company, or your car's warranty, but having a 24-hour number to call is kind of a big deal if you happen to have some misfortune that's beyond your repair skills.
16. A radar detector
If you're one of those people who refuses to use a radar detector because you have Waze, consider this: on the open road, there are far fewer people to populate the Waze app than in the city, and there are also far less grocery store doors to trigger a false alarm. A good detector, like the Escort Passport Max 2, can alert you of a cop coming up from two miles away.