There is really no such thing as 'full coverage". Most people use this term to refer to physical damage coverage.

Physical damage coverage consists of collision and comprehensive coverage.

Generally, collision insurance covers damage to your automobile caused by collision with another object or by upset.

Comprehensive insurance covers damage to your automobile from vandalism, theft or glass breakage. (Most lienholders require physical damage coverage if you are financing or leasing your vehicle.)

Now, with a "total" loss, you insurance company will pay you your vehicle's "actual cash value." If you mean collision and comprehensive coverage when say "full coverage" and you can continue to afford this coverage, you need to decide if you should continue to carry this coverage until it stops making economical sense to carry it.

In other words, you should stop carrying this coverage when your deductible and this coverage's premium starts to equal your vehicle's "actual cash value."

Each person is different, but if you have a $500 deductible and the car's value is $5000 then the most you can recover in a total loss is $4500. Is it worth it to you to pay the physical damage premium in return with the option of re-couping that money in the event of an accident then you should keep the full coverage.