Domain mapping- will all the links work?

Hi,
Currently I am in the early stages of working on a couple of websites using WP multisite and subdomains. I will need to change these at sometime to their own domain names.
I understand that I will have to use domain mapping at some time.
The question is: will all the links automatically work to content and images after mapping or do they have to be set manually? If so, am I better to map the sites now and save myself a lot of work later?
Thanks