I have issues asking for beta readers amongst writers. Because I don't like reading much, and am very picky about what I do read, I feel that I can't return the favour. So if someone volunteers or is super keen, then I may consider them, but generally I'm uncomfortable with a beta read. As for friends and family, I don't want them reading my stuff and having the possibility of that impacting their perceptions of me. Also because I don't trust that they don't just give me 'Oh, you wrote a book, that's cute' kind of response, like they do for my photography. I'd like to be taken a bit more seriously, or not at all.
The few I've had mostly came from a writing forum that shut down last year. I'm no longer in touch with all except one of them now unfortunately. I've had my boyfriend read over a few short pieces for me recently and I'm considering asking him to look over a longer piece of work. He's brutally honest, which in one way is fantastic but on the other hand is completely terrifying because it's hard not to take his comments to heart.