Apartments

Binder

The binder should be the building. If you have multiple buildings, you can create one binder per address.

Asset

Assets are always the equipment. In this case, it's the building and its equipment that require maintenances.

Sector

Sectors could be used to group units by floor or by type. This will help you filter the assets to find what you're looking for quickly.

Maintenance

Once you've created your assets, you can assign the required maintenances to keep them in excellent condition.