How deep is your sand bed?

[SamMule]

I see a lot of differing opinions on how deep your sand bed should be.
How deep is your sand and why?

I set mine at around 1.5" deep enough for some good surface area, but shallow enough that I can clean the crap out of it.

 

[lapin]

0 to 6 inches

 

[Og_Reef]

1 in