Αυτό ισχύει και για εμάς, εκτός αν έχουμε βάρδια.

This applies to us too, unless we have a shift.

Breakdown of Αυτό ισχύει και για εμάς, εκτός αν έχουμε βάρδια.

• αυτός: this
• έχω: to have
• για: for
• και: too

Questions & Answers about Αυτό ισχύει και για εμάς, εκτός αν έχουμε βάρδια.

What does ισχύει mean here, and how is it used?

ισχύει (3rd person singular of ισχύω) means to be valid / to apply / to hold true.
It’s commonly used with:

• Αυτό ισχύει. = This applies / This holds true.
• Αυτό ισχύει για… = This applies to…
• Ισχύει ότι… = It’s true that…

Here it agrees with the subject Αυτό (singular), so you get ισχύει (not plural).

Why is it Αυτό and not Αυτή or Αυτός?

Αυτό is the neuter demonstrative pronoun meaning this. Greek often uses the neuter to refer to an idea, statement, rule, or situation, not a specific masculine/feminine noun.
So Αυτό ισχύει… is like This (fact/rule) applies….

Why does it say και για εμάς? What role does για play?

για + accusative can mean for or to/for (in terms of applicability). With ισχύει, the pattern ισχύει για κάποιον is extremely common and means it applies to someone.
So:

• ισχύει για εμάς = it applies to us
  And και adds too/as well:
• ισχύει και για εμάς = it applies to us too

Why is it εμάς and not εμείς?