During your doula training discussion of having a reliable back up is minimally discussed, and yet is an aspect of your business that is vitally important. In fact when interviewing a potential client they will often ask about happens if you have another client in labour at the same time.
On the most basic level, a back up is a doula you know or know of, that has agreed to step in for you at a birth or a postpartum gig, at the last minute, should you be at another birth or become ill or if you are away for a period of time close to your clients due date.
Common practice for a birth doula that has to call in their back up, is that they will pay the back up a certain amount per hour up to 50% of the full doula cost. That way if you only need a back up for a few hours, it won't cost you half your fee. If you are doing a volunteer birth or a low cost birth then you need to let the back up know this ahead of time. Just because you agreed to this job doesn't mean they have to do something for free or low cost.
For a postpartum doula that calls in a back up for a short period of time such as a shift or two, the doula will usually pay the back up the hourly rate they would have gotten paid.
Finding the right back up is also critically important. Who you choose should be similar in philosophy, personality and experience. Of course you can't clone yourself but you should be able to find someone who isn't the complete opposite to you. Remember, this doula and what they do will reflect on you, and your reputation. And your client hired you, if they need to have someone else in the birth for whatever reason, they would like a reasonable facsimile to you.
However if you live in a small community where there are very few doulas you may be stuck with what you get. In a pinch you could ask your client if they interviewed anyone else they liked who you could contact for a back up. Networking, meeting other doulas for coffee and getting to know your community will put you in contact with other doulas too. And if your community is really sparse in doulas, host a training to get more doulas in your area. Once you find a doula or two or three, it could be the start of a beautiful relationship or business.
Being a back up is a very large responsibility too. Before accepting a particular back up job make sure you can actually be available. Letting down a fellow doula, unless you are at your own clients birth, will not play well in your community and make it difficult for you to get back ups yourself. I once had a back up completely let me down. We had been starting a mutual relationship of back up work that could have developed into something but when I needed this doula the most they let me down and I ended up attending two births back to back for 48 hours of full support for two clients and I was completely broken at the end of it. Not sure the second client really got the support they needed. It may sound petty but I never contacted them again for back up support. They were clearly unreliable and I wasn't willing to risk being let down again.
When working with a back up make sure you have all the financial expectations sorted out ahead of time. Some will even have a back up doula contract. These financial arrangements could include, paying the doula for being on-call. $50-$100 per client and then if they are called into the birth they would get the rest of the back up fee. You should let your back know whats happening, if they might be called out or just on stand by and then when the birth is over let them know they are no longer on call.
Having a consistent back up is also a way to have someone to talk to about the birth,your clients and those gross things your family and friends are sick of hearing about.
So while you are putting your business together, make finding a back up a priority, and often times you only have to look as far as your doula training. Back ups ultimately help you and your clients.