10 year old domain VS brand new domain

[sinicline]

Hi All

I am new so first of all hello. I look forward to using the site now I have decided to try and learn more about SEO.

I have a small business and a website to go with it. Both the business and the domain name are 10 years old now however I would like to rebrand the business including changing the domain name.

Does an aged domain really count that much towards your SEO with Google or would it be ok to gradually phase out the old domain name over the next year in favour of my new domain name?

Or is there any wise suggestions on how to best handle this situation such as keep the old domain name but forward it to the new domain?

I have spent a good few hours searching Google and like most advice via the internet its fairly conflicting.

Any advice or hints and tips to help with my situation would be fantastic.

Thanks