"have had" or "have been having"

English as a Second Language English Vocabulary, Grammar and Idioms
1

Fill in the blank:
“I love your car”. "This old thing? We ______ it for 15 years"

Is it better to fill “have had” or “have been having” ? Please tell me the difference between them cos they usually make me confused.

Thanks so much in advance

2

We do not use the progressive with ‘have’ when it means ‘possess’.