So, this is more of a general question.
As I’ve been learning Blender for 3+ months now (I guess), I’ve been sculpting my characters as one big object from the default sphere. When I look at tutorials, a lot of them bring in other meshes and sculpt the character’s body parts separately.
Now, I haven’t even touched on animation and rigging yet, but I do want to do that eventually. I was wondering if sculpting my character’s parts separately would effect animating and rigging them.
Thanks! 
The sculpt generally isn’t what gets rigged. IME, they’re usually too high poly and lacking in the topology that lends itself to good animation or rigging.
Sculpting from one big object will not be an issue for rigging/animation for a few reasons.
For one you can always separate the mesh into individual parts later if you decide you want to organize it that way. Secondly, what people typically do when they start with a sculpt is retopologize the sculpt into a lower-poly mesh- makes the character easier to rig and gives smoother animation playback. So, chances are you won’t be working with that base mesh anyway
No, we do that in Game Characters all the time… It started back when memory was a premium, so we were trying to keep the cost as low as possible. Also, it has the added benefit of taking care of clothing clipping into the body. Where if it is a complete body, you will have to deal with that, especially in Blender, which does not have the greatest physics. We usually will create a mask so that parts of a mesh that would be problematic, are hidden from display, and still available when clothing changes to something else. You will need to determine when and where something like this would need to be done, as It is easier to create a full base mesh, then re-topo the result for rigging, and hide what you don’t need or even delete it if it is never visible.
Watch this for an overview of the process…
Happy Blending!