If I'm recording JPEGs at the camera for a client who wants Adobe RGB, the client will get original files in Adobe RGB. Otherwise, they will get JPEGs in sRGB.

If I'm converting to JPEGs from raw files in post-production, the output can similarly be Adobe RGB or sRGB.

When recording raw files, it does not matter what the profile setting is at the camera! The appropriate raw profile will be used in post-production to convert the data to the working color space I've chosen, and then from the working color space to the output color space. (That said, my default profile for JPEGs is sRGB, and it gets changed ONLY if the client needs Adobe RGB.)

SOME graphic arts houses prefer Adobe RGB from photographers, because they are used to getting crappy color from photographers who adjust images without calibrating their monitors. Adobe RGB gives them a smidge more ability to adjust it from an original JPEG. (But it's less than they think!)

MOST photo labs printing to silver halide paper (conventional wet process) prefer to receive all files as sRGB. Such photo labs don't accept raw files, and some require you to TELL THEM if you use Adobe RGB, so they can interpret your files correctly. That is because they STRIP OFF the metadata and embedded sRGB profiles when importing files to their servers.

HIGH END service bureaus with top notch inkjet printers from Epson or Canon sometimes allow clients with laptops or notebooks to plug them into their networks and print directly. Doing so allows immediate, on-the-fly conversion from a raw file, through the ProPhoto RGB working color space, to the exact printer/paper/ink profile in use. That is the FINEST printing system available, provided the image is adjusted on a fully calibrated monitor (see below). Such a workflow is 16-bits, too (although 12- or 14-bits at the camera). That greatly improves subtlety of color reproduction.

JPEG files prepared for the Internet ALWAYS should be saved in sRGB color space, because 99% of users do not have monitors capable of displaying much more than sRGB.

Whatever profile you use, if you adjust your images and save JPEGs, you should use a FULLY calibrated and custom-profiled monitor capable of displaying the output color space of choice. NO monitor can display typical working space profiles like ProPhoto RGB, or the color range of a 16-bit high end inkjet printer driver. A few can display a bit more color gamut than Adobe RGB. Even more can display 99% of Adobe RGB. But the vast majority are 8-bit monitors that display only sRGB — and only when properly calibrated and custom profiled.

Proper monitor calibration and custom profiling REQUIRES a hardware device (colorimeter or spectrophotometer), and the software designed to work with it. I can't stress enough what a HUGE difference proper calibration and profiling can make in your workflow. USING a calibration kit does require reading ALL the instructions and directions, and probably requires more than a few passes to get the monitor brightness tuned properly. But once set, what you see on the monitor is extremely close to what you get from the printer.