As a teacher I would say there is no excuse. There are two Winter Breaks and Spring Break. Age and grade matters greatly too but, in my eyes it's just bad form. Would you be ok with a teacher missing the first week of school just because of their spouses military schedule? I never quite understood parents who felt the need to take their kids out for separate vacation periods?
'Our' kids, 'our' decisions! We did it twice and they were middle/high school, and they did great with no problems. They were both honor students and we had good relationships with teachers and principals. No regrets.