What heights are the parts and the total height of the staff when it's all put together?

The Section is 17cm high. The D20 Topper is 9.3cm. When the parts of the Deluxe D20 Staff of Critical Hits are fully assembled they create a staff that is 59cm long. When the parts of the Good & Evil Box Set are fully assembled they create a staff that is 104cm long. Of course you can purchase additional Sections to make your staff longer!

How strong is the staff? Could you use it as a cane/walking stick?

We've gone to great lengths to make the staff as strong and sturdy as possible. The staff is hollow so it's not as strong as a solid wooden cane. But we've had customers successfully use our prototype staves in place of a cane/walking stick.

Much will depend on the weight of the staff-bearer and we don't yet have a weight rating.

How tight do the parts stay together? Is it just for show or could you take it out with you?

The staff parts friction fit together and it's definitely intended to be taken out and about as a prop, not just hung on the wall!