If you only have time to use one you should post on Facebook and link the Facebook page to Twitter so that your posts on Facebook automatically appear on Twitter. Keep the posts on Facebook short so they make sense on Twitter. You need to figure out where your clients are to make good use of your time. If you do direct to consumer, figure out who your consumers are and whether they are on Facebook, LinkedIn, Twitter, Snapchat, and so on. Focus your time where they are. This will require some research on your part.