At my company you keep your seniority number which determines when you will get recalled. As far as seniority time, however, that does not accrue. For example, the one year probationary period will continue when we return since we were furloughed with between 6-8 months of seniority. Eventhough it's been more than a year since we were hired, time spent on furlough doesn't count. Nor does it count towards any benefits. In essence, the only thing your seniority is good for while on furlough is to get you called back in order.