Domain Age

I have a client who purchased a new domain for a project he plans on launching in a year and a half or so.

He wants to improve the domains age before he actually uses it for the launch and is thinking about simply putting it up a dummy site of sorts (or maybe a page that says "coming soon") to build the domains age.

My assumption would be that the site would have to be at least semi-active for it to gain any SEO equity for domain age. Or does it just have to be crawled occasionally?

Anyone have any experience with this?

Domain age is a ranking factor, but i dont think it's much of a ranking factor anymore. I think it would be better to launch the site and set up a nice long slow organic-looking seo campaign. I have successfully ranked brand new domains in less than a year doing this.

I've also heard buying a domain name for more than 1 year helps, but again, i havent seen any evidence that this is a deciding factor by any means.

Also, I have one domain name that ive owned since 1996, but that never helped it outrank amazon