The short answer
Windows already shows storage usage across connected drives and lets you choose default drives for several kinds of new content. What it does not provide is a single what-if plan for future installs, reserved headroom, and cleanup choices across every drive.
A cautious multi-drive workflow
See every connected drive
Open Settings → System → Storage → Advanced storage settings → Storage used on other drives. Select each drive to review its category breakdown and remaining capacity.
Choose your own headroom target
Decide how much free capacity you want to preserve on each drive for updates, temporary work, and future installs. Treat it as a planning target—not space Windows has reserved for you.
Set sensible defaults
Open Where new content is saved to choose default drives for new apps, documents, music, pictures, and videos. Check individual desktop installers and game launchers separately because they can maintain their own library locations.
Plan the next large install
Compare its expected size with usable capacity after your headroom target. Prefer an appropriate drive rather than filling the system drive first and reorganizing later.
Review before moving or removing
Use supported application controls when moving apps or libraries. For personal files, verify backups and ownership before changing anything. A large file is not automatically disposable.
When Storage Spaces is—and is not—the answer
Microsoft Storage Spaces can group eligible drives into a pool and create virtual drives with simple, mirror, or parity layouts. Microsoft describes simple spaces as performance-oriented without drive-failure protection; mirror and parity layouts add different forms of resiliency.
Do not create a pool merely to avoid deciding where files belong. Pooling changes storage architecture and deserves a separate backup and recovery plan.
What a planning tool would need to add
Manual Windows steps, safe planning principles, and a browser-local estimate tool. It does not inspect or change your PC.
A local read-only scan across connected drives, automatic categories, headroom rules, and explained cleanup or placement proposals. Every file change would require approval.
Primary sources
- Microsoft Support: Storage settings in Windows — other-drive usage, default save locations, disks and volumes, and Storage Spaces.
- Microsoft Support: Storage Spaces in Windows — requirements, layouts, resiliency, optimization, and drive removal.
- Microsoft Support: Manage drive space with Storage Sense — supported automatic cleanup behavior and its system-drive scope.