Subdomain to new subdomain move

See Moving_WordPress.

i check that link . but tough for new ones like me.

any way, one more question.

my old site have about 300+ posts. 150+ categories and 200 tags etc.

i want to know when i shift all data to new domain from my old subdomain, i need to use every old page redirects from htaccess to new ones like..
old post 1 to new post 1
old post 3 to new post 3 etc
OR
a single 301 redirect from old to new one?