Do these fit any Schick razor?

No. They are made for Schick Silk Effects handles. Other Schick systems, including Hydro Silk, use different refills.

How do they compare with Schick Hydro Silk refills?

Hydro Silk cartridges have five blades and a wider lubricating strip. These have three blades and a simpler head, so the shave is lighter and less cushioned.

Are they good for sensitive skin?

The lubricating strip helps reduce drag, but three bare blades still pass over the skin. Shavers with very reactive skin often prefer a razor with more cushioning or a shave gel.

Can I use them on my face or bikini line?

They are designed for legs and underarms. There is no trimmer edge, so precise work around the bikini line is harder than with razors built for it.

How often should I change a cartridge?

Schick generally suggests a new cartridge once the blades feel dull or the lubricating strip has worn away, which for regular shaving is often every week or two.