1. Your great aunt gives up her license, but maintains a car for you to drive her to appointments.

Usually the person insuring a car is a licensed driver. However, if you still own a car but no longer drive, you may be able to list someone else as the primary driver.

In this case, your aunt could ask her insurer to exclude her and name you as the primary driver. The auto insurance company would use information about you, such as your age, gender and driving record, to help determine the premium for the policy.

Have your aunt call the car insurance company or agent she used before giving up her license. An insurer is more likely to accommodate special circumstances for a customer with a good track record with the company.

2. Your sister is laid up for six months with a broken leg, so you move in and use her car to help out.

If you visit for a couple of weeks, then your sister's policy probably would extend coverage to you as a "permissive driver" -- someone she lets borrow her car occasionally. However, if your stay extends beyond a month or so, you should be added as a driver on the policy.

Insurance companies want information on all the licensed drivers who live in the household and have regular access to the car. Neglecting to tell the company about a driver who shares the household could create a sticky situation if that driver crashed the car.

Your sister should let her car insurance agent or company know that you're living with her. Once she's up and around again and you move out, she can remove you from the policy.

3. You make extra cash chauffeuring elderly neighbors to the store.

Call your car insurance company if you're using your own car. Check whether your errand-running counts as business use of the vehicle. If you're being paid, the insurance company could see it as business use and refuse to cover any accident that happens while you're driving on paid errands.

Ask your neighbors to check their own policies if you're using their cars. If you don't own a car of your own, consider non-owner car insurance as an option.

4. Your grandmother asks you to drive her to a monthly bridge game.

In most cases, your grandmother's policy would cover you as an occasional "permissive driver." Still it's a good idea to double-check coverage with the car insurance company.

And some include tricky exclusions. Cheap car insurance policies, for instance, sometimes exclude everyone but the named drivers, or they exclude permissive drivers under the age of 25. In some states, insurers are allowed to include "step-down provisions" in their policies, which reduce the policy's liability limits to the state-minimum requirements when permissive drivers are using the car. These types of limitations are more common with nonstandard, inexpensive policies.

5. You move in with your elderly father as a permanent caregiver and take over driving her car.

If you live in the home and are the only one driving the car, you need to be on the policy. In fact, if your father never intends to drive again, it might make sense to have the vehicle transferred into your name and get your own insurance policy for it, to avoid any issues.

As a permanent caregiver, you have enough to deal with without worrying about insurance. Call the insurance company and discuss your options; don't assume that the existing policy can simply be renewed, especially if your father gives up his license. Since you live in the home now and are the main licensed driver, you need to make sure you have the right coverage.

The bottom line? It's always worth a call to the insurance company if you're going to drive someone else's car as a caregiver to verify coverage.