Will this cut through hardened bolts and fasteners?

Yes, the 1/4" jaw opening is designed for standard bolt sizes. The cutting edge handles hardened steel fasteners, but avoid forcing it through material larger than the jaw capacity — that wears the blades faster.

Is this cutter suitable for wire and cable, or just bolts?

Both. The same 1/4" jaw works cleanly on wire, cable, and small fasteners. The compact head lets you get into tight spots without sacrificing leverage.

What maintenance does this need between uses?

Wipe down after use to remove metal shavings and moisture. A light oil on the pivot joint keeps it smooth. Store in a dry space to prevent rust on the cutting edges.