The reason I repot is a noticeable jump in growth. I repot annually, usually starting in February. The jump in growth is because some of the media has started to break down, retaining water, and most probably a drop in media ph. If the media doesn't or didn't break down I would certainly wait to...
Phragmipedium 'Sorcerer's Apprentice' is a sequential bloomer that will bloom for most of a year. Very aggressive growers that will thrive with good care and possibly still bloom if neglected.