As a mom, I spend a lot of time shuttling from place to place in the car. Having just gotten a new car a few months ago, mine still feels pretty neat. I put more effort to keep it clean and organized because it doesn't have years of wear and tear. Regardless of whether your car is new or old, there are easy ways to keep it up that don't take a lot of effort.
I recently purchased a small plastic coupon organizer from the dollar store to manage important information that we keep in the car. If you've ever been pulled over or in a fender-bender, you know how important it is to have your insurance and registration handy.
I bought a small first-aid kit for around $10 at Target that has some basics in it like bandaids, advil and antiseptic wipes. It's small so I keep that with a package of wet wipes in the side pocket of the driver's side door. In the pocket of the front passenger door I have a couple plastic bags and a small roll of paper towels for spills, sickies, etc. Our car came equipped with a jack and jumper cables, but if yours doesn't, I'd suggest having some for emergencies.
Because we live in a pretty warm climate, I don't keep too much else in the car for emergencies. If we lived somewhere cold or snowy, I would have a couple small blankets, water and antifreeze. Most of the driving that I do is within city limits and typically pretty close to home so I don't worry too much about us being stranded for a long time. If you spend time driving in isolated areas, you'd want to be prepared with some bottled water, snacks, etc.
To keep the car tidy, I make it a habit to pick up the trash, toys, clothes, etc. that inevitably end up in the car every day. Rather than having to clean a giant mess every so often, doing a daily sweep makes it easier to deal with a small amount. Like most chores, doing it more often makes it take less time and energy.
What do you keep in your car for emergencies?