What's the Best Practice for showing Badge Count beside Profile Pic on all posts? (Caching?)

I would at least upgrade it to API v2 with something like this untested code:

<#assign userData = (liql('SELECT login, user_badges FROM users WHERE id="${res.author.id}"').data.items) />

${userData.user_badges.size}

That won't solve for having to repeatedly call this within a thread where the same author appears multiple times though. The article on caching states that it's not worth caching a users login and avatar, so following this argument it's probably not worth caching the badge count 😇