You have to weigh the pros and cons of credit cards and credit in general.
As people have mentioned credit scores can be pulled to determine insurance rates, allow you to rent a car, rent a apartment, and ive even heard of employers pulling it. Credit cards themselves are not bad if you stay on a budget and pay them offer, ive used a credit card for over a decade now and never once paid interest, yet i get 1% back on everything, its not a lot but its nice knowing everything is 1% cheaper when I shop.
With that said if you have had trouble with taking out loans, running up credit card debt, etc... then for you the cons out weigh the pros and in that case I would cancel them as they damage they do is far worse than not being able to rent your dream apartment or having to pay a little extra on insurance.