Don't overdo it. Use your instincts. This cannot be stressed strongly enough. You are selling a product and Casting Directors and Agents are buying it. Just as in commerce, the law of supply and demand applies.
All actors audition.
There are never as many jobs as there are actors that want them. For example, when theatres have Equity auditions for a show, there are only so many Equity slots available, so Equity actors lose jobs to non-Equity actors. And non-Equity actors lose jobs to Equity actors. It's happened to everyone. Don't take it personally.