For simple-to-medium boards you can assemble it yourself... No help if you're making a motherboard or whatever though.

Downside to this: it takes a long time, I have to source the parts myself, and I can't separate design or programming errors from soldering errors. (There will be many of those) I have not figured out a system to So: Having JLC do the assembly is a no-brainer for the projects I've done.