This is a question that struck every home mechanic. Yes, doing the job yourself brings pride and satisfaction, but it is very important to know the consequences of certain common mistakes that a trained professional just wouldn’t make — but that you might. How do we know the thin line between bringing it in to the shop and DIY (do-it-yourself)? The answer is complex and varies according to the system of the car and the type of car itself.

The automobile is a complex piece of machinery that can be divided into eight subcategories:
• The engine (and all of its mechanical components)
• Suspension and Frame
• Brakes
• Passenger Comfort
• Performance Electronics
• Transmission
• Tire and Wheels
• Aesthetics

There are things that you can do yourself without too much worry, like working on the aesthetics of the car, where the worst thing that can happen is the car might not look too good. And then there are things you can do, but should be extremely careful in doing, like working on the brakes of your car. It is your responsibility to figure out what kind of repair your car needs, and how critical it is for safety. Working on your brakes, your wheels, and your suspension is relatively simple, but the smallest mistake (leaving a bolt loose for example) could cost a high price.

Your second responsibility is to know your limitations, which are determined by two factors:
• Your capabilities. How good are you?
• Your equipment. Do you have all the right tools?

You need to understand how the system works, and why you are repairing the component. If you do, then you can check the first one, if you don’t, it’s time to stop and do research, ask questions and anything you need to do to understand WHY you are doing what you are doing. Then, it’s time for the second one, do you have all the right tools to do what you are about to do? And most importantly, do you have all the right tools to fix the car if something goes wrong? The main example here is air conditioning work, as you need the proper equipment to depressurize the system. If you don’t this equipment, you can’t fix it. It’s unsafe to you, the people around you, and the environment.

The third factor is time. Car repair can be very time consuming and sometimes not worth it for that reason alone. Do you want to be fixing your car the whole week to save a couple hundred bucks? It may be worth it to pay and get a professional job done while you work at something you can do to pay for it. Besides, if the repair doesn’t work, you can complain to the mechanic. If your home repair goes wrong, you are on your own.

Last but now least (and probably the most important one): which car are your working on? As a professional mechanic I assure you that working on a Honda Civic is not the same as a Jaguar X-type. Here is an anecdote: one guy comes to my shop and tells me, “I was changing the rear brakes on a X-type, I did one side just fine but when I did the other the caliper came apart.” Well, any Jaguar specialist knows that the piston on the opposite side on the X-types screws the opposite way. He, however, did not, and so he thought he was screwing it in, but he was screwing it out. Now he had to pay three times the amount of what he was supposed to pay in the first place.

In conclusion, look at these factors to decide whether to do it yourself or to take it in:

1. Do you know how to do it?
2. Do you know why you are doing it?
3. Do you have the right equipment?
4. Do you have the time?
5. What car is it?

A rule of thumb you could use: if you want to save money, then do the basic maintenance and aesthetic work, and leave the rest to the pros.