So I am just a hobbyist, I create in ZB for fun and the challenge. I will render in ZB with passes and usually compose in Photoshop. I do not make assets for games or for animation, again just stills. So what might be some possible reasons to do any of this work outside of ZB? I can see maybe going to Blender for easier mesh work but what else should be considered? Better texture painting app? Anything else to consider?
The new hard surface functions in the upcoming 4R7 may make it even less likely to stray outside of ZBrush. Texture painting inside ZBrush is IMHO already very good. If you need more stuff such as particles, I suggest Substance Painter as it is reasonably priced and easy to learn.
For most hobbyists the end result is probably a still image and not animation, so a good renderer would be a wise investment if you can’t get perfect results rendering in ZBrush.
If Zbrush meets your needs, then there is no reason to work with anything other than zbrush.
There are a number of tools that may specialize to a greater degree in something or other that Zbrush also does, that some people may prefer using for specific tasks. But there are few things that can’t be done in Zbrush if it suits you.
Perhaps the most common reason people have ever had for leaving Zbrush is to use a more powerful, full featured photorealstic render solution. Some people get great results in Zbrush, but it has some distinct limitations. Pixologic is addressing this with the Keyshot Bundle for the new version which is priced to be accessible to hobbyists. You might be interested in checking that out. But even that isn’t strictly necessary if you’re content with the results you get for your own uses in Zbrush.
Appreciate the replies. Think I have just been doing too much reading and exploring, just seems there a ton of workflows out there for high to low poly, which seems more game orientated in nature, but might be a more efficient way to work (Substance Painter/Designer or nDO/dDO). Perhaps I am trying to complicate something for no reason.
People working for game output have exacting needs in terms of geometry and complex texture mapping. People working for cinematic output may have specific needs in terms of displacement and normal mapping. People working for 3d print output have exacting needs for geometry to be constructed in a certain way to a precise scale. Zbrush is a great tool in any one of those workflows, but people working for those outputs are likely to use other specialist tools as well, especially where animation is concerned as ZB is not an animation tool.
If your output consists chiefly of still images for your own satisfaction, PLEASE don’t let yourself get worked up reading about other tools, and other people’s workflows. You enjoy a tremendous amount of freedom in that scenario, and your only concern should be what makes you happy.
Just because I might make use of other tools in certain situations, doesn’t mean I’m happy doing it. I’m generally happiest when I can stay in Zbrush, even if there’s another tool that might be nominally better at a specific task.
Thank you for the insight, now I can get back to Zbrushing 
Perhaps I am trying to complicate something for no reason.
LOL, yes, spend a couple years learning ZBrush first, it takes some time to Master it. 
I have tried to cross this bridge a few times. I have played with Poser, daz3d, carrara. I looked at a few others. I even bought a year license for Messiah 3d… the issue there was a lack of any support. I have tinkered with Blender. Most of these packages take a lot of Zbrush fussing to get your models imported properly, with the exception to blender. But Blender has a tough interface to learn, not intuitive. Blender is free and open source.
I’m a hobbiest too. I would love to animate my models. But cheap and easy don’t seem to come hand in hand with 3d animation. I myself may have to take another crack at Blender. At least Blender has a giant user support group.
Might as well throw in my 2 cents’ worth.
As a 1/6 scale collectibles customizer and someone who’s looking to start his own line of 3d printed mech collectibles, I find ZBrush to be the perfect software for the majority of my needs when it comes to prototyping, concept modeling and creating custom accessories. If I could, I’d rather complete my projects in ZBrush from start to finish.
Thing is, ZBrush lacks a proper measuring tool. The transpose line isn’t accurate enough to give me the kind of precision I need for ball-joint and peg measurements as well as parts clearance.
I had to import my ZBrush models as obj or stl files into Sketchup when making precisely sized ball joints and peg holes. The thing with Sketchup is that it acts very differently from most other 3d software–it loves n-gons and triangles, and its Boolean tools crash when working with high poly surfaces. It took a lot of experimenting before I figured a workaround for this problem.
But with 4R7 boasting some powerful low-poly geometry brushes (please let there be a measuring tool in 4R7 too!), I hope to be able to work exclusively in ZBrush. Even if 4R7 doesn’t have a measuring tool, at least the topology made from the hard surface tools would be simple enough that I can easily work on the model in Sketchup to make the necessary ball joints and peg holes.