"Hi Experts,

After i switch my site HTTP to https, Google hasn't re-indexed my site.
How long must I wait?"

No!!

adding HTTPS won't get you an SEO ranking boost, but not adding it might affect your Google rankings over time. ... These are all ranking signals that the site isn't doing well, which Google translates into "I should rank this unsecure site lower and reward a website with a secure connection instead."

adding HTTPS won't get you an SEO ranking boost, but not adding it might affect your Google rankings over time. ... These are all ranking signals that the site isn't doing well, which Google translates into "I should rank this unsecure site lower and reward a website with a secure connection instead."

Google will switch between https and http (and vice versa) without any noticeable link juice loss, as long as the links (apart from the prefix) are identical. However, if you want to make sure that your links return to http and not leave it to Google or chance, then a 301 redirect will force the change.