First of all, I really like that you’re disciplined to do this exercise for an hour every morning! At that rate you will be a skilled sculptor in a month or two. I can already tell you’re well on your way.
There’s not a particular philosophy behind or benefit to keeping your sculptures a single piece. In some cases, as you’ve pointed out, a single mesh is definitely a hindrance. In these situations, separating your sculpture into parts is perfectly fine.
When gestural sculpting I tend sculpt as much as I can in a single mesh until it becomes a problem. Chopping into pieces adds slight complexity to the workflow because switching between pieces is not very intuitive with Blender. But over all it’s a small inconvenience.