Did you know it’s possible to schedule your re-tweets? I’m not talking about the manual retweets (RT) where you put “RT” in front of the tweet. I’m talking about native re-tweets: those that use Twitter’s re-tweet button.
A couple of years ago, manual RTs were the way to go on Twitter. In the last few years, however, many Twitter users have come to appreciate the official RT—so much so that for a period of time, some people were publicly shaming those who used the manual RT.
My personal feeling is that unless you’re manually adding something to the original tweet (for instance, by adding a comment before “RT”), you probably should just use the new RT. It’s the right thing to do—it gives full credit to the original twitterer, and it’s easier since it won’t require you to shorten the original tweet.