Shopping is often a spontaneous activity. You might pop into the local department store to buy something that catches your eye or even make larger purchases without knowing what you want beforehand. Unfortunately, car buying is one activity where stepping onto the lot without a plan can have significant consequences.

Even the best dealerships can't help you without knowing what you want or need, so it's good to have a plan before you leave your house. Even if you need a car on short notice, such as after an accident, you should still spend some time getting ready for the experience. Here are three reasons why planning can save you money, time, and frustration at the dealership.

1. You Might Not Realize Your Needs

Is it good enough to buy any vehicle with four wheels and an engine? Probably not, but you might be surprised at how many factors go into finding a car that fits your lifestyle. How big is your gas budget? How often do you take road trips? Do you typically drive by yourself, or do you need something to haul a family of four around? How many other cars does your household own?

These questions and many more can make the difference between a car you drive because you have to and a vehicle you love to get into every day. Before heading out, write down as many requirements as possible and divide them into "wants" and "must-haves." Keep this list on hand and consider bringing it to the dealership with you so that you only need to look at cars that fit your requirements.

2. You Can't Eyeball Your Budget

It's easy to guesstimate how much you can afford to spend on a car every month, but costs such as insurance, gas, and routine maintenance can reduce your available budget. Working out your actual affordability limit at the dealership can be challenging, and you shouldn't expect the dealership financing team to understand your specific financial needs.

Even if you don't do any other planning before shopping, you should sit down and determine your upper limit for the total cost of your car and your monthly car loan. While spending less than your maximum is often a good idea, keeping this limit in mind can help you avoid a costly mistake that may haunt you for many years.

3. You Don't Have All Day

If you don't have a good idea of what you're looking for, the sales team at the dealership can't direct you to the vehicles that fit your needs and budget. The more information you have, the easier it is to focus on a few cars that meet your exact requirements. Ultimately, you'll have fewer distractions, spend less time at the dealership, and have a better chance of finding the car you want.

Remember that buying a car is an important financial decision. By planning ahead, you can help the team at the car dealership find the perfect vehicle for your daily needs.