A car insurance contract can be invalidated for several reasons we sometimes ignore. We have to be careful about what we say or don't say to our insurer to be sure to be covered as much as we can. Here are some mistakes to avoid to be well covered.Not declaring previous convictions Most of the time, we think that if we don't reveal a past conviction to our insurer, we will pay less and nobody will see anything. The thing is that it is illegal not to declare to your insurance your past convictions because, if they investigate you and realise that you have lied, you won't be covered and could even pay back what the insurance covered in the past. Same for the accidents, you need to declare any accident you've been involved in, responsible or not. If you do that later, claims will be rejected and your policy could be cancelled. So, better be honest with your insurer and declare any accident or conviction of the past years, even criminal ones. Not getting your eyes tested It seems not important but it really is. There are certain requirements regarding your sight that have to be checked to be able to drive. If your sight doesn't meet the requirements, you are breaking the law and your driving license can be revoked. Failing a sight test can also invalidate your car insurance. Not revealing modifications If you start "pimping" your car with different wheels or special paint, you have to tell your insurer. The value of your car will increase and as a result, so will your premium and the cost to repair it. Under-insuring There's no point with under-insuring your car because if your insurance finds out you've lied, this could cancel your policy. Also, when you'll need to claim, the insurance will only give you the amount you said your car was worth. Understating your mileage Try to be precise on the mileage you're going to have per year. There's no point in underestimating it, it will be good for cover anyway. Buying budget or cut-down cover Try to buy a policy adapted to your needs, it's a false economy to buy a budget or cut-down one. Sometimes if you just shop around and compare, you can find a fully comprehensive policy at an interesting price. Not checking for errors Be careful not to make mistakes when you give your details to your insurance like age, gender, occupation or address. Also keep them accurate because a possible claim could be rejected by your insurer if they are not. Not demanding discounts Don't hesitate to ask for discounts to your insurer. You never know what he can offer you, sometimes you can cover two cars on the same insurance or add another 'named' driver to your policy, which makes you pay less. Not protecting personal information It seems obvious, but if you share personal information on social media or if you don't make your account private for instance, insurers won't accept to cover you because it's considered as a risky behaviour. So try not to share dates when you are away or say where you are at a certain moment. Neglecting your driving or your car Try to drive carefully because if you have many accidents, it will of course have an impact on your car insurance. Also try to use your garage if you have one, because it's safer for your car and will reasusre the insurers. Locking your car is also something obvious but really important, like maintaining it and testing your vehicle safety regularly. If you don't take care of your car and you have an accident, costs can be high and you could face criminal charges for driving a vehicle in a bad condition.