As a hiring sales manager, I do my own recruiting and keep a network that I tap into and ask around about good potential candidates. You never know when an opportunity might tap you on the shoulder. Your sales resume is the key to land you an interview, so it is important to keep it updated at least every year.
If you are open to opportunities, then it is critical that you update it quarterly so that at a moment's notice, you can submit and apply to a job while the opportunity is hot. I have came across situations where, I have reached out to candidates and they have told me that they were interested but then take days to send me their resume. When their resume comes in, it is poorly written, not customized to the job opportunity, full of errors and I can tell that they quickly put it together. You might not think about having your sales resume updated, until you are out of a job and actively seeking, but you might be passed up on a great opportunity if you are not prepared. If you are a passive candidate, it is important to keep the sales resume ready to sell yourself for any opportunity. Take a look at your sales resume and make sure it is up to date.