When should I change the sand?

I have a dune scorpion, and he has created more than a burrow. It's a massive, spacious cavern underground, and I hate to destroy it just to clean it's tank.

So, how often should I replace the sand? I see a few droppings, but they seem really dry and dessicated.

You don't have to change the sand. You only need to spot clean, scorpions are very OCD when it comes to their burrows and scrapes. They will usually deposit any rubbish at the mouth of their burrow, you can then just take it out.
I would not worry about a few droppings in the tunnels, it is probably not worrying him much.

That's great....but one day, I didn't see the scorpion anywhere and I used a spoon to dig up parts of the tank, and found nothing.

I was afraid he escaped so I frantically dug some more until I found him, but in the process, I mixed the sand with the droppings, so now the droppings are somewhere buried in the sand, out of sight.

How stressed are scorpions when they have to rebuild their home?

It could cause the scorpion a fair amount of stress. They will not only stress because they have to dig a new burrow which causes the scorpion to be out in the open, which they dislike but also the action of destroying the burrow because it will think it is being dug up by a predator.
Just remember to rather spot clean in the future

I'd hate it too if someone came to smash my house in order to clean it. Lol

the only reason that you should ever completely change the sand is if there's a lot of ants or an alarming presence of mites

exoticvirus wrote:

the only reason that you should ever completely change the sand is if there's a lot of ants or an alarming presence of mites

Mites aren't usually much of a concern in desert scorpion enclosures...they are extremely prone to dessication and the lack of humidity is rather inhospitable to them.

I agree, a complete sand change is almost never really necessary.... just spot clean... and indeed, try to relax... if you don't see the little beastie most of the time it is happy that way... try to lay off digging it out and try to give it a little time. If it's more secure in it's home it will venture out more. At least that is my experience. My P. Cavimanus, didn't came out... period.
Now, she is walking around late in the evening... and becoming more daring... so to speak;)