How often should I tweet?

The answer, of course, is that it depends. Here are some considerations:

• Post Twitter updates regularly enough so that your followers see that you're active and engaging.
• Do not post so often that you might be considered spam.
• You can tweet the same post if you want to, but avoid doing it over and over again in rapid succession. It's better to space it out and also rephrase if you can.
• Try not to be sporadic in your posts. Be consistent in the number of tweets and space them out throughout the day.
• Definitely do not "shotgun" tweets and post a bunch of posts all at once.
• It can help to use a tool like HootSuite to create posts in advance and schedule them to be sent throughout the day/week. You can import posts via spreadsheet and use that to ensure that you're posting regularly and staying on topic.