It's all down to personal choice and how likely you think you are to have an accident. The loss of no claims bonus can dramatically affect the premium you pay now and future premiums. If you commute to work on a daily basis by car you would be a lot more likely to have an incident than If you use your car occasionally and through the day time and it makes a lot more sense to protect it. If the sum of money is low to protect it, it is worthwhile.