One of the most important aspects of car servicing is making sure that the car is safe. A way to do this is to have car safety inspections done. Your car needs to get a safety inspection in order to ensure that it is roadworthy, so that you don't harm yourself or other people in traffic by driving an unsafe vehicle. It's not always easy to know when you need to have your car checked, as there are quite a few situations when it's necessary. In order to make sure your car is always roadworthy, you need to know when to have it inspected.
If you make major changes in your vehicle that aren't standardised by the manufacturer, you'll need to have your car inspected. For example, if you change your engine to the same type of engine that you had before, which was an original part of the vehicle, you aren't changing the qualities of the car but rather just updating the engine. However, if you build your own engine, or put an engine in that isn't made for your type of car, you'll need to have a car safety inspection done to make sure it's still roadworthy.
You also need to have a car safety inspection done if you change the dimensions of your car. If you have structural work done, making the car longer or wider, the dimensional information in your car's manual won't longer be correct, and therefore you need to update the information. It's also important to do this after dimensional changes as your car might need additional equipment to stay roadworthy. Your old suspension might not, for example, be appropriate to use if you've raised or lowered your car significantly. This is something you'll find out with car safety inspections and therefore be able to do something about it quickly.
If you've installed more seats in your car, you also need to have it inspected. This is important, as car seats are surrounded by quite a lot of safety regulations. You need to have appropriate seat belts that fulfill all safety demands. You might also need to have air bags protecting all seats, or at least make sure that the existing air bags aren't placed in a way that could possibly injure someone sitting in your new car seats if they were to be inflated. The car safety inspector will tell you about these things and also inform you exactly what you need to do in order to make the new car seats safe.