How many times should it take for someone to get in the ear aids to be comfortable to wear?

It is highly unusual to have to continually remake hearing aids to fit comfortably.

Yet, to better answer your question, please share with us the make and model of your hearing aids, size, etc and your general experiences so far with them.

I’ve had similar problems with fitting molds. I now have “open ear” type aids, but one of them won’t stay in when I bend my head down. How common is this?

With the open ears, your audi should be able to put a dome on it that fits your ear better.

What type of open fit device do you have?

The tubings on open fit hearing aids come in various lengths and insertion depths. You may need a shorter tubing to snug the hearing aid up. I know when I fit open aids and someone is inbetween sizes, I always go for the larger or the two so it is more comfortable. If I pick the shorter, I may run the risk of irritating the top of the ear.