Hi cn1ght,
Thanks for the update … and you certainly made a great quality/value choice!
Congratulations on your new mattress 
Yes … a mattress protector is a good idea for any mattress regardless of whether it is latex or any other material. There is more about the pros and cons of the different types of mattress protectors in post #89 here that can help you choose the type that is the best “match” for your criteria.
Generally it doesn’t need to be washed if you have a mattress protector on top of it that can easily be removed and cleaned and which will protect the mattress from stains and accidents along with the body fluids and skin cells that we release each night so you can keep your sleeping surface in a clean and hygienic condition. It will also protect the warranty because most warranties are voided if there are any stains on the mattress. For the most part … mattress covers only need to be spot cleaned when necessary or vacuumed once in a while but if the care instructions indicate that it can be washed or dry cleaned without damage then you can clean them once in a while as well if it becomes necessary.
I’m looking forward to your feedback when you’ve received your new mattress and have had the chance to sleep on it for a bit.
Phoenix