My girlfriend has a rule. If she does not wear something for a year, she gets rid of it. Her rational is if she hasn't used it in the past year, why should she believe that she will need it next year...
It's your car and up to you and you alone. Some are passionate about their cars and would feel they lost a part of themselves and their identity if they got rid of it, others are very pragmatic and wouldn't see the point of having something that didn't get used enough to warrant keeping. If you sell and come to regret, buy another.....