How many pairs does it actually hold?

There are 22 open cubbies, so roughly 22 pairs if you use one cubby per pair. Smaller pairs can sometimes share a cubby, and tall boots may need a cubby to themselves.

Will tall boots fit in the cubbies?

Not upright. The cubbies are sized for standard shoes and sneakers, so tall boots usually have to lie on their side or go on a top shelf.

Does it need to be attached to the wall?

It is freestanding and does not require wall mounting. A tall, wide unit can still tip if climbed or bumped hard, so anchoring it is wise in homes with small children.

What are the dimensions?

It is about 47.2 inches wide and 11.8 inches deep. Check your hallway or closet width against that 47-inch figure before buying.

Is it worth it compared with a closed shoe cabinet?

It costs less than most closed cabinets and holds more pairs for the money. Closed cabinets hide clutter and protect shoes from dust, so pick this one if access and capacity matter more than looks.